Understanding and mitigating the downwash effect is crucial for architects, urban planners, and city dwellers alike. As we navigate the complexities of wind downwash and its aerodynamic underpinnings, we uncover a compelling narrative of urban adaptation. We will discover how strategic design and innovative solutions can tame these gusty challenges, turning potentially unwelcoming urban spaces into havens of calm and comfort. Join us as we explore five key strategies to mitigate the downwash effect, promising a future where urban design harmonizes with the natural elements to enhance the pedestrian experience.

What is the Downwash Effect?

The downwash effect is a wind-related phenomenon commonly observed in urban environments, especially around tall buildings and skyscrapers. This effect occurs when wind strikes the face of these high structures and is deflected downwards, creating strong downdrafts at street level. These downdrafts can significantly increase wind speeds on the ground, leading to uncomfortable and sometimes hazardous conditions for pedestrians. The intensity of the downwash effect is influenced by various factors, including the height and shape of buildings, their orientation, and the surrounding urban layout.

Wind Flow Patterns

The downwash effect occurs when undisturbed high-energy wind from higher up is deflected down towards the ground by a building or structure.
This results in a notably uncomfortable zone at the base of the tall structure. While this effect is frequently observed in regions with towering buildings, it can also arise in lower urban settings. Essentially, under suitable conditions, the downwash effect can manifest in both urban and suburban areas, demonstrating its broad potential impact across different environments.

Recognizing the Downwash effect

One of the key methodologies for comprehending and addressing the downwash effect is the application of Computational Fluid Dynamics (CFD). This sophisticated tool allows architects and urban planners to simulate and scrutinize the intricate patterns of wind flow, pressure variation, and velocity around high-rise buildings. Utilizing CFD, we can effectively visualize how wind behaves in relation to the distinct shapes and configurations of urban structures, pinpointing zones where downdrafts and turbulence are most intense. These insights, derived from CFD simulations, are instrumental in formulating specific strategies that not only refine urban design but also enhance pedestrian comfort in wind-affected areas. As we progress through this article, we will explore how CFD can be adeptly used to identify and mitigate the downwash effect, gradually making its identification more intuitive and straightforward.

Comfort plot

Unlike the cornering and channelling effects, which exhibit distinct patterns in a comfort plot, downwash doesn’t present a unique shape that’s easily identifiable. However, a significant stretch of discomfort, aligned parallel and close to the base of a building, can be a strong indicator of downwash’s influence. This pattern suggests that downwash could be contributing to making the area less conducive for certain activities.

Directional Wind Speeds

Below is a prime example of how directional wind speed results, captured through Computational Fluid Dynamics (CFD), can be instrumental in identifying the downwash effect. The image presents a slice of velocity taken at the base of a building, where the flow dynamics are visible. Using a vector visualization with arrows, we can observe the distinct pattern of wind as it interacts with the building structure. These arrows vividly illustrate the wind’s trajectory: initially striking the building’s facade, then being forcefully directed downwards, and eventually spreading outward at ground level. This graphical representation is crucial in identifying the downwash effect, as it not only confirms its presence but also provides essential details about its direction and strength. Such visual insights are invaluable for urban designers and planners in developing strategies to mitigate the impact of downwash in pedestrian areas.

5 Strategies for Mitigating the Downwash Effect

In the quest to mitigate the downwash effect in urban environments, two particularly impactful strategies stand at the forefront: diverting the wind further up the building and reducing the wind’s energy. These innovative and practical approaches offer promising solutions to the challenges posed by the intense downdrafts created by tall structures.

The first strategy involves architectural and structural modifications to divert wind at higher elevations away from pedestrian zones. This can be achieved through various design elements such as aerodynamic building shapes, strategically placed louvers, or wind-redirecting façades. By altering the wind’s path before it reaches ground level, we can significantly diminish the intensity of downwash experienced on the streets.

The second strategy focuses on dissipating the wind’s energy. This involves employing materials, designs, or additional structures that absorb or break up the wind’s force, thereby softening its impact when it reaches pedestrian areas. Techniques such as incorporating green walls, porous surfaces, or specialized architectural elements can play a crucial role in reducing the kinetic energy of downdrafts.

In the following sections, we will delve deeper into these strategies, exploring how they can be effectively implemented in urban planning and design to create more comfortable and safer pedestrian environments amidst our ever-growing cityscapes.

1. Building Design

By integrating specific architectural features at an early stage in building or site design, we can significantly influence how wind interacts with structures, thereby reducing the intensity of downwash at the pedestrian level.

Key among these architectural interventions are setbacks and stepped building designs. Setbacks involve creating recessed sections in a building’s façade, effectively breaking up the wind flow and redirecting it before it reaches the ground. This not only disrupts the downward trajectory of the wind but also helps in dispersing its energy more evenly across different levels. Stepped buildings, on the other hand, offer a tiered approach where each level acts as a platform to divert and weaken the wind’s downward force. These steps function like a series of barriers, progressively diminishing the wind’s velocity as it descends the building’s height.

Both setbacks and stepped designs are more than just aesthetic choices; they are strategic elements that play a crucial role in the aerodynamic performance of a building. By incorporating these features, architects and urban planners can proactively shape the wind flow around skyscrapers and high-rises, making the areas at their base more comfortable and safer for pedestrians. This approach aligns perfectly with our objective of diverting the wind further up the building and reducing its energy, offering a harmonious blend of form and function in urban design.

The stark contrast between the baseline and setback designs is evident. In the setback design, we observe a marked reduction in high-energy wind reaching the pedestrian level. This is clearly depicted in the streamline images, where the wind’s trajectory is visibly altered, demonstrating less downward force as it interacts with the building’s staggered façade. Correspondingly, the pedestrian comfort images reveal a significant improvement in the areas around the building. The discomfort zones, prominently visible in the baseline design, are noticeably reduced in the setback version, indicating a more pedestrian-friendly environment. These results underscore the effectiveness of incorporating setbacks in urban architecture, not just for aesthetic appeal but for tangible improvements in pedestrian wind comfort.

2. Street-Level Structures

Street-level structures, such as canopies, awnings, and strategically placed barriers, serve as immediate buffers against the downdrafts caused by tall buildings. These structures are designed to intercept and redistribute the wind’s flow, effectively softening its impact on pedestrians. Canopies and awnings, for instance, can provide overhead protection, deflecting the wind upwards or sideways, away from the walking paths. Similarly, barriers like walls, screens, or even sculptural elements can disrupt and break up the wind flow, reducing its velocity as it reaches people on the streets.

This method of intervention is particularly effective because it addresses the downwash effect precisely where it’s most experienced—on the sidewalks and public spaces that thread through our urban landscapes. By integrating these structural elements into our cityscapes, urban designers and planners can create more hospitable and comfortable outdoor environments, enhancing the overall pedestrian experience in areas prone to aggressive downwash effects.

In the baseline scenario, without canopies, the images reveal a more pronounced downwash effect, with streamlines indicating a direct downward wind movement reaching pedestrian level. This corresponds to larger discomfort zones in the pedestrian comfort images, highlighting areas where wind speeds are likely to be uncomfortably high.

Conversely, in the canopy-equipped scenario, the streamline images show a notable diversion of wind flow. The canopies effectively intercept the downward wind, redirecting it horizontally or upwards, thereby reducing the direct impact of downwash on pedestrians. This alteration in wind trajectory is clearly evident and translates into improved pedestrian comfort levels. The comfort images in this scenario show reduced zones of discomfort, indicating that the canopy structures have successfully mitigated the intensity of the downwash effect at ground level.

These results demonstrate the efficacy of canopies as a practical solution for urban areas plagued by strong downdrafts from tall buildings. By incorporating canopies into street designs, urban planners can enhance the pedestrian experience, making city streets more welcoming and comfortable despite the challenges posed by the urban wind environment.

3. Landscaping

Trees and shrubs can act as natural windbreaks, absorbing and dispersing wind energy. When strategically placed, these green elements can significantly reduce the velocity of downdrafts from tall buildings, creating a buffer zone that protects pedestrians from harsh winds. The choice of plant species is crucial here – selecting those that are resilient to wind ensures their effectiveness as a barrier.

Moreover, the arrangement of these green spaces plays a pivotal role. By designing clusters or rows of trees and shrubs in key areas where downwash is most prevalent, we can create a more continuous and effective barrier. This natural approach not only addresses the practical aspect of wind mitigation but also contributes to the aesthetic and ecological value of urban environments.

Incorporating landscaping as a mitigation strategy offers a sustainable and visually appealing solution to the challenges of urban wind conditions. It demonstrates a harmonious integration of nature within our cityscapes, enhancing the overall quality of life for urban dwellers while effectively tackling the downwash effect.

In the scenario with trees added, there is a noticeable change in both the wind streamlines and pedestrian comfort levels. The trees act as natural barriers, disrupting and diffusing the wind’s downward trajectory. This diffusion is evident in the streamline images, where the wind appears to be less focused and more dispersed around the tree-covered areas. Consequently, the pedestrian comfort images show a significant improvement, with reduced discomfort zones, indicating a more pleasant and less windy environment at ground level.

These visual results underscore the effectiveness of trees in mitigating the downwash effect. By strategically placing trees around high-rise buildings, urban planners and designers can create a more sheltered and comfortable pedestrian environment, leveraging the natural buffering capacity of greenery to counteract the challenges posed by urban wind conditions.

4. Urban Planning Considerations

Here, we turn our focus to urban planning considerations, particularly vital during the master planning stage. At this stage, the flexibility to experiment with building positions and orientations offers a unique opportunity to proactively address wind comfort in urban design.

Urban planning considerations encompass a broad range of strategies aimed at optimizing the layout of buildings and public spaces to minimize the adverse effects of downwash. By strategically positioning buildings, planners can influence the direction and intensity of wind patterns in urban areas. This involves careful consideration of the orientation of buildings, ensuring that their placement doesn’t exacerbate wind conditions at the pedestrian level.

Additionally, the arrangement of streets and open spaces plays a crucial role in wind mitigation. Designing streets that are not directly aligned with prevailing wind directions can help in dispersing wind energy, reducing the formation of strong downdrafts. Incorporating open spaces, such as parks and plazas, provides areas where wind can be dissipated before it impacts pedestrian zones.

The effectiveness of strategic urban planning in mitigating downwash is vividly demonstrated through a set of four images, derived from Computational Fluid Dynamics (CFD) simulations. These images compare two scenarios: one where a tall building is positioned on the windward side of a street block, aligning with the prevailing wind direction, and another where the same building is moved to the leeward side of the block. The top row of images illustrates the levels of pedestrian comfort, while the bottom row focuses on the wind streamlines to depict the downwash effect.

In the first scenario, with the building on the windward side, the streamline images clearly show a pronounced downwash effect. The wind, unobstructed by other structures, strikes the building directly and is funnelled downwards towards the pedestrian area, resulting in high-energy wind patterns at ground level. Correspondingly, the pedestrian comfort images indicate a significant area of discomfort, highlighting the intense impact of downwash in this configuration.

Conversely, in the scenario where the building is relocated to the leeward side, there is a noticeable reduction in the downwash effect. The streamlines in these images depict a more dispersed wind flow, as the building is now shielded from the direct path of the prevailing wind. This alteration in wind dynamics leads to a notable improvement in the pedestrian comfort images. The zones of discomfort are substantially reduced, indicating a more pleasant and less windy environment for pedestrians.

These comparative results illustrate the impact of thoughtful building placement in urban planning. By considering the direction of prevailing winds and strategically positioning tall buildings, urban planners can significantly mitigate the downwash effect, enhancing the overall comfort and safety of pedestrian areas in urban environments.

5. Computer Simulations and Wind Studies

The critical role of Computer Simulations and Wind Studies cannot be overstated in the effective mitigation of urban wind phenomena like the downwash effect. In urban design and architecture, Computational Fluid Dynamics (CFD) emerges as a particularly powerful tool. This technology allows for an in-depth analysis and visualization of wind flow patterns, pressure distributions, and velocity fields around buildings and through urban streetscapes.

CFD simulations offer a window into the complex dynamics of wind behaviour in built environments. They enable designers and planners to model various scenarios and assess how different building shapes, orientations, and urban layouts influence wind patterns at the pedestrian level. This foresight is invaluable in predicting and addressing potential wind comfort issues before they materialize in the physical world.

Additionally, these simulations are instrumental in conducting wind studies that inform the design process. They provide detailed insights into how wind interacts with structures, identifying areas where wind speeds may be excessively high or where downwash effects are most pronounced. Armed with this information, urban designers can make informed decisions to optimize building features, landscaping, and street layouts to mitigate these effects.

In essence, the integration of computer simulations and wind studies into urban planning and architectural design represents a confluence of technology and creativity. It allows for the creation of urban spaces that are not only aesthetically pleasing but also comfortable, safe, and harmonious with natural elements. This approach underscores a commitment to enhancing the quality of urban life by transforming wind challenges into opportunities for innovative and sustainable design.

Explore CFD in SimScale

Discover More

Conclusion

Addressing the downwash effect in urban design is crucial for creating comfortable, sustainable, and inviting cityscapes. Strategies like aerodynamic building designs, effective street-level structures, landscaping, and strategic urban planning, coupled with the insights provided by Computational Fluid Dynamics (CFD), offer a multifaceted approach to enhance pedestrian wind comfort. These methods demonstrate a harmonious blend of technology, creativity, and practical urban planning. As we continue to evolve our cities, integrating these strategies ensures that our urban environments are not only aesthetically pleasing but also livable and welcoming, harmonizing human experience with the natural dynamics of wind.

The post Building Downwash: 5 Key Strategies to Counteract Urban Wind Discomfort appeared first on SimScale.

Let’s get you up to date with SimScale’s new key features released in Q2 2023.

1. Custom Wind Comfort Criteria/Plots

SimScale already provides today a variety of different Pedestrian Wind Comfort Criteria, like Davenport, Lawson, London LDDC, NEN8100, and more.

Still, this list can never be exhaustive as there are a multitude of locally used and adapted comfort criteria that are either required by local authorities or have proven to be well suited to the specific local conditions.

SimScale enables our users to define their own comfort criteria with custom wind speed ranges and percentage thresholds.

With this new possibility, a range of new comfort criteria can be created. Here are some examples:

• CSTB Wind Comfort Standard
• Auckland Wind Comfort Criterion
• Melbourne Wind Comfort Criterion
• Bristol Wind Comfort Criterion
• Israeli Wind Criteria
• Murakami Wind Comfort Criteria

2. Thermal Resistance Networks for IBM

This feature is a natural extension to the Immersed Boundary solver and is already available for Conjugate Heat Transfer. It provides thermal resistance networks like two-resistor or star resistor models in the simulation setup and allows you to define detailed components like chips or LEDs as customized components. This avoids the necessity for very fine meshes for those often tiny components.

Users can define a thermal resistance network (TRN) by assigning the top surface of a cuboid as a TRN.

Model the chip as a simple cube in a CAD model or replace the detailed 3D model via ‘Simplify’ on SimScale.

3. Multiphase: Surface Tension

With the addition of surface tension, users of the new multiphase module will be able to improve the accuracy of multiphase results for surface tension dominant flows like microgravity sloshing, capillary flows, microfluidics, etc.

4. Ogden Hyperelastic Model

We have added this model to better simulate highly elastic rubber. In the animation below, you can see the movement of two solid parts coming together and separating again. There is a hollow rubber seal between them with significant deformation.

Use Case & Benefits

• Accurately simulate rubbery and biological materials at high strains
• Increasing hyperelastic functionality

5. Cylindrical Hinge Constraint

The Cylindrical hinge constraint boundary condition replicates the behavior of a fixed hinge. The assigned surface is constrained such that only rotational motion around the hinge axis is free.

SimScale can automatically detect the axis of the hinge based on an assigned cylindrical surface, but the boundary condition also allows for a user-defined input.

6. CAD Swap Improvements

When replacing one CAD model with another, it isn’t always clear what worked and what didn’t. With this feature, we add clarity so that users know what was successful and what requires their attention.

7. Parametric Studies

Boundary conditions can now be parametrized to run multiple simulations with a button click. Some examples are:

• Electronics: change inlet flow rates, change the heat load on parts
• AEC: change inlet flow rates to understand the impact on cooling strategies
• Rotating Machinery: change the inlet velocity and rotational velocity and compare designs

8. CAD Extrude Operations

Extrude is similar to move, although it will maintain the same cross-sectional area — often very useful.

This video shows one move operation followed by one extrude operation. Notice how the extrude option maintains the shape of the adjacent surfaces.

9. Distance Measurement

This is a highly requested feature, and I think we have answered nearly all use cases with this first iteration. We now offer the ability to measure the length/area of an entity and also measure the distance between two entities.

Take These New Features for a Spin Yourself

All of these new features are now live and in production on SimScale. They are really just one browser window away from you!

If you wish to try out these new features for yourself and don’t already have a SimScale account, you can easily sign up here for a trial or request a demo below. Please stay tuned for our next quarterly product update webinar and blog.

The post NEW Features: Custom Wind Comfort Criteria, Thermal Resistance Networks, Surface Tension, and More! appeared first on SimScale.

It is, therefore, crucial to ensure that wind turbines are designed optimally for their specific operating conditions to extract the maximum possible amount of energy. In this article, we discuss how wind turbine design can be enhanced and accelerated with simulation using CFD and FEA tools to achieve optimal efficiency and performance.

Wind Turbine Design

There are essentially two types of wind turbines, horizontal-axis wind turbines (HAWT) and vertical-axis wind turbines (VAWT). These are turbines where the rotation of the turbines is parallel and perpendicular to the ground, respectively. The vast majority of wind turbines in use today are horizontal-axis types as they have proven to be more efficient than the vertical-axis types.

Betz Limit and the Extracted Wind Power

The theoretical maximum efficiency of a wind turbine is 16/27 or 59.3%, as determined by German physicist Albert Betz in 1919. In other words, only 59.3% of the kinetic energy from wind can be captured by a perfectly designed wind turbine in open flow that experiences no losses in operation. This theoretical maximum is known as the Betz limit, and all wind turbines are designed to approach this limit to the greatest extent possible. Betz law demonstrates that “The power extracted from the wind is independent of wind turbine design in the open flow. Therefore, it is impossible to capture more than 59.3% of kinetic energy from the wind” [1].

The output power of a horizontal wind turbine blade can be derived as follows:

$$ P = \frac{1}{2} \rho A V^3 $$

where

• \(\rho\) is the air density (\(kg/m^3\))
• \(A=\pi R^2\) is the rotor’s surface area (\(m^2\))
• \(V\) is the velocity of incoming wind flow (\(m/s\))

How Much Can A Wind Turbine Produce?

According to Wind Europe, formerly known as the European Wind Energy Association, an average onshore wind turbine can produce 6 million kWh over the span of a year, while an average offshore wind turbine can produce more than double this power. This is not the maximum output these turbines are capable of and is rather a function of the amount of wind energy available for conversion.

Turbine Blade Design

The design of wind turbines has largely to do with the design of the turbine blades. These blades are designed to maximize the transference of the kinetic energy from the wind to the blade from a specific direction known as the angle of attack to facilitate the continuous rotation of the turbine. The optimal angle of attack for a wind turbine lies between 25° to 35°.
The most important considerations in the design of wind turbine blades are outlined below:

1. Wind Turbine Materials

The materials used to manufacture the wind turbine blades have to satisfy certain physical requirements for their operation. They have to be lightweight to turn faster. They have to have high strength, high stiffness, resistance to fatigue, and weather resistance to be more durable and able to withstand the adverse effects of the elements of nature.

2. Number of Turbine Blades

The number of blades on a wind turbine plays an important role in its efficiency. Most horizontal-axis wind turbines have 2 or 3 blades, and this is for good reason. The more blades a turbine has, the greater the torque it can generate, but the slower it rotates due to increased drag from wind resistance. Turbines with one or two blades will theoretically achieve a higher efficiency due to significantly reduced drag. However, they will be much less stable and will experience high vibration. This instability may lead to damage over the long term. Nevertheless, having more blades on a turbine is more expensive not only because of the extra blades that need to be manufactured but also because the supporting tower has to be built stronger. The ideal number of blades for a horizontal-axis wind turbine has thus been generally accepted to be 3 blades to satisfy the requirements for efficiency, durability, and high performance [2].

3. Wind Turbine Blade Shape

The shape of wind turbine blades must have an aerodynamic profile that enables them to rotate as the wind impacts them from a variety of angles. They have a similar curved design to the wings of airplanes, known as airfoils. The curved blade causes a pressure differential between the air that flows over the blade (which flows faster) and the air that flows under it which is what causes lift and the blade to rotate. The most efficient wind turbine shape will be able to be suitably impinged by oncoming air but also minimize drag. To achieve this, turbine blades are usually twisted along their length and taper down in width towards the tip.

4. The Tip Speed Ratio (TSR)

The tip speed ratio (TSR) is defined as the ratio of the speed of the tip of the turbine blade to the speed of the wind. It is an important parameter in the design of wind turbines as it is proportional to their performance. The TSR is dependent on the shape of the wind turbine, as well as the number of blades it has. Generally, the optimal TSR lies between 7 and 8 for most three-blade horizontal-axis wind turbines, but it may vary depending on the specific design [3].

In a nutshell, a well-designed wind turbine should be sturdy, stable, durable, and with blades that are capable of capturing most of the wind’s energy with an optimized TSR for power generation.

Wind Turbine Simulation using CFD and FEA

The parameters that govern the performance of wind turbines can be deconstructed into numerical values, equations, and CAD models, which can be fed into simulation tools as data or boundary conditions. The effects of these parameters can then be quantified and visualized as the simulation is run, and the necessary adjustments can be made to optimize the design. Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) tools are crucial in this process.

CFD Simulation of Wind Turbines

Computational Fluid Dynamics (CFD) is a numerical analysis tool that allows engineers to study the flow of air (and fluids in general) around and through objects such as the blades of a wind turbine. The data on wind is usually known and is generally predictable from information obtained from field studies. The idea is to translate this information into usable simulation data for analysis.

The information may include parameters such as inlet and outlet velocities, pressures, temperatures, etc., that specify the state of the fluid at the edges of the simulation domain. This allows engineers to easily vary the properties of the simulated wind and study how the wind turbine would behave under different conditions.

FEA Simulation of Wind Turbines

Finite Element Analysis (FEA) is also a numerical analysis tool, but it is used instead to investigate the physical properties and shape change of an object by analyzing its structural integrity and mechanics. This allows engineers to minimize their need to create physical prototypes of the design, at least until sufficient testing and adjustments are made virtually.

Engineers create 3D models of the wind turbine components (namely its rotor, hub, nacelle, and tower), and through the use of advanced algorithms, these geometrical shapes are divided into smaller elements collectively called a mesh. The finer the details of these models via proper meshing, the more accurate and reliable the simulation of the fluid dynamics and structural behavior would be. Upon meshing, FEA simulations can be performed to analyze displacements, forces, and pressures on the turbine blades and other parts.

CFD and FEA are used in tandem to analyze the performance of a wind turbine model. In simple terms, FEA simulates the physical structure of the turbine, and CFD simulates the fluid flow around it. The designing aspect comes mostly from the FEA simulation, where the turbine material, shape, and size may be adjusted to achieve optimal results.

After completing the simulation, the results are analyzed to evaluate the performance of the wind turbine design. The amount and quality of data for analysis depends on the quality of the simulation as well as the quality of the geometry creation and physics setup. At this stage, small changes can be made to these factors, and the simulation is run again to determine if any improvements in the simulation results can be achieved.

SimScale for Wind Turbine Simulation

To determine the characteristics of a wind turbine design, engineers must conduct tests on various environmental factors that will naturally vary in real-world conditions, like air speed and temperature. This can be accomplished using online computational fluid dynamics (CFD) simulations through platforms like SimScale. SimScale provides cutting-edge technology in the field of engineering simulation in a wide range of engineering fields, including rotating machinery like wind turbines.

The primary focus of such simulations lies in examining the design of the wind turbine blades and experimenting with different design variations to find the optimal design for the desired outcome. For instance, flat blades, which are one of the oldest blade designs still in use today, are losing popularity due to reduced rotational efficiency caused by wind resistance during the upward stroke- which is why they are referred to as drag-based rotor blades. Nevertheless, flat blades are cost-effective to manufacture, straightforward to replicate in terms of shape and size, and require less specialized expertise for implementation.

Whether it is flat blade designs or curved blade designs, there is room for improvement through online simulations and the evaluation of various design iterations. This encompasses testing different materials using CFD and FEA simulations, exploring variations in length and width, and assessing performance in different seasonal and environmental conditions. SimScale is a valuable tool for users to optimize their wind turbine designs by simulating them at various air velocities in parallel. For example, check out the following wind turbine simulation projects:

• HAWT: Wind Turbine Simulation of Airflow around the Blades
• VAWT: Vertical Axis Wind Turbine

In fact, there are several reasons why using Simscale can set you and your wind turbine design project apart, some of which are elaborated below:

Cloud-Native Computing for Wind Turbine Simulation

Due to its cloud-native nature, SimScale enables engineers to run multiple simulations simultaneously instead of one after another, reducing the time required for design iterations. Users do not need to worry about expensive hardware, complex installations, or limited resources. SimScale’s cloud-native platform enables engineers and designers to bypass these issues and simplifies the simulation process down to a simple “sign-in and simulate directly in your browser” type of process. The application of such simulation tools, along with the power of cloud-based computing technology, makes it possible to cut simulation times down from days to mere hours, allowing engineers to complete more design cycles in a given time frame

Advanced CFD and FEA Technologies

Simscale offers CFD simulation with a mix of the best open-source and proprietary CFD solvers, which have been seamlessly integrated into the SimScale interface. These solvers can cater to the simulation of compressible and incompressible flow as well as laminar and turbulent flows with turbulence models, such as LES Smagorinsky, SST-DDES, k-omega SST, and k-epsilon.

The SimScale FEA tool allows for the simulation of an object’s response to static and dynamic loads as well as vibrational analysis to determine the rigidity and durability of the object. With
SimScale’s cohesive ecosystem of simulation products, you can optimize both the FEA and CFD components all in the same place and in real time, allowing for virtually endless iterations of simulation runs to achieve the best results possible.

Lower Cost and Faster Time-to-Market

The entire purpose of engineering simulation is to minimize the cost of physical prototype building and testing. The reduced cost associated with traditional simulation is even more pronounced with SimScale due to the added efficiency of cloud-native computing. With SimScale, the costs of expensive hardware and software licenses are eliminated. Quicker innovation can be achieved with better resource management in the research and development phase, which ultimately leads to faster time-to-market.

Seamless UX and Proven Workflows with CAD Software

SimScale empowers engineers to innovate faster and enables users not so familiar with the intricacies of engineering simulation to still take advantage of the resource through a simplified and guided simulation process reinforced by a dedicated, real-time support team and a user-friendly interface. Experienced engineers can easily navigate SimScale’s interface from start to finish with little to no help, and it takes an inexperienced user little time to become adept, especially after following the plethora of guides, tutorials, and educational content.

SimScale’s online post-processer renders results in easy-to-understand and highly detailed formats that can allow the user to compare and evaluate an array of useful output data, capture images and animations, and more. Running wind turbine simulations online and applying design changes directly on the spot is possible with SimScale via your web browser without the need to install any specialized software.

SimScale also has seamless integrations and proven workflows with multiple CAD software, enabling users to design, modify, and update their CAD designs, which would automatically update in SimScale so that they can run simulations in a more streamlined and efficient manner, thanks to the power of CAD associativity.

Case Study: Energy Machines Use SimScale to Optimize Wind Turbine Designs

Simulation is indispensable for the design of wind turbines, and Simscale is a state-of-the-art resource that engineers can use to run their simulations to the highest degree of accuracy and speed. With the unparalleled power of cloud computing, SimScale’s easy-to-use interface, and live expert support to guide you, your wind turbine simulation can be performed quicker, more accurately, and more efficiently than ever before.

Here’s what the engineers at Energy Machines, Danish service providers of integrated energy systems, said about using SimScale in their design of vertical-axis wind turbines: “Being able to run many simulations in parallel on the cloud has been very useful and saved us a lot of time. Using SimScale has reduced our wind turbine testing by weeks. By simulating on the cloud with more cores than on a personal computer, we have been getting results about 3x quicker than if we run it locally, as before. We also save time on how quick it is to set up many similar simulations by duplicating and changing geometry or other input parameters.” Read more about how Energy Machines optimize wind turbine designs with engineering simulation in SimScale.

The post Wind Turbine Simulation and Design appeared first on SimScale.

In this blog post, we explore the complexities of pedestrian wind comfort, delving into the far-reaching impacts of the channeling effect and unveiling five strategies to combat its relentless grasp. Join us on this expedition as we uncover innovative solutions to restore tranquillity and ease to the wind-ravaged streets, reimagining them as havens of pedestrian comfort.

What is the Channeling Effect (Funneling Effect of Buildings)?

To comprehend the impact of the channeling effect on pedestrian comfort, it is crucial to delve into its intricate mechanisms and dynamics. The channeling effect, an intricate phenomenon prevalent in urban environments, shapes the wind patterns that pedestrians encounter. As wind traverses the built environment, its encounter with building gaps, corners, and intersections sets off a chain reaction of accelerated airflow, intensifying its force and creating localized areas of turbulence. In this section, we explore the underlying principles of the channeling effect, unravel its contributing factors, and gain insight into how it affects pedestrian experiences. By understanding the intricacies of this phenomenon, we can better grasp the challenges it poses and pave the way for effective mitigation strategies.

Wind Flow Patterns and Pressure Distribution

The channeling effect is a wind phenomenon that occurs when the wind is funneled between buildings of close proximity, increasing wind speed and intensifying the wind as it flows through the channel. This funneling phenomenon is commonly observed at intersections where tall buildings create a focused pathway for the wind. As the wind passes through the gaps and spaces between the buildings, its speed intensifies, resulting in higher wind velocities. The buildings can also influence the direction of the wind, deflecting or redirecting it within the channeled zone.

Recognizing the Channeling Effect

One of the most powerful tools for understanding and mitigating the channeling effect is Computational Fluid Dynamics (CFD). This advanced technology enables engineers and designers to simulate and analyze the complex wind flow patterns, pressure distributions, and velocity fields that occur within urban environments. By harnessing the capabilities of CFD, we can visualize how wind interacts with the unique geometry of buildings and street layouts, uncovering areas of accelerated wind speeds and turbulent conditions. This valuable insight gained through CFD simulations empowers us to develop targeted strategies that enhance urban design and improve pedestrian wind comfort. In the following sections, we go through the journey required to identify the channeling effect using CFD. This becomes easier over time, and identifying the effect will become increasingly intuitive.

Comfort Plot

Comfort plots provide valuable information about the comfort levels of specific areas within a designated space. These plots depict zones where pedestrian activities are either comfortable or uncomfortable due to the influence of the channeling effect. By examining comfort plots, designers can identify areas prone to intensified wind flow and gusts, which directly impact pedestrian comfort.

Look for higher comfort categories in areas such as gaps between buildings, long straight streets with tall buildings, and converging lines in building layouts. Comfort plots usually highlight an issue, and we need to apply some intuition to identify the effect. In our further discussion, we will delve into the analysis of wind speeds and directions, exploring how they can better contribute to identifying the channeling effect and its subsequent impact on pedestrian comfort.

Directional Wind Speeds

Given the comfort plot, we can identify that an area in our design exists that is uncomfortable due to some wind effects. But we could not concretely identify the channeling effect from the cornering or downwash effect. To do this, we need to look at the results from different directions, inspecting mainly the wind speed results. By examining the wind rose diagram, we can identify the prevailing wind direction for initial clues to potential channeling locations.

Looking closely at the same area we identified as uncomfortable, we can see high wind speeds passing between the buildings. As the flow moves closer to the constricted place, the wind increases until it separates around the corner of the building. It is this pattern you can look out for to positively identify the channeling effect.

5 Strategies for Mitigating the Channeling Effect

1. Building Design

When it comes to mitigating the channeling effect, building design plays a crucial role. Through careful consideration of orientation, shape, and features, buildings can be designed to minimize wind impacts and create a more comfortable environment for pedestrians.

Key points to consider:

• Take into account building orientation and shape to enhance wind dispersion.
• Incorporate setbacks or indents in building facades to disrupt wind flow.
• Design features that act as wind deflectors or windbreaks.

Let’s consider a simple change that adds a bevel to the shape of the building:

In our design for a new mixed-use building on a windy urban street corner, where the prevailing wind direction is from the southwest, we introduce a chamfer on the upper half of the building’s windward corner. This beveled edge skillfully redirects the wind upwards and over the building, effectively preventing it from being funneled between the buildings at ground level. As a result, wind speeds are reduced, and pedestrians experience improved wind comfort. The previously intense wind speeds are relieved, and the affected area is reduced, creating a more harmonious and inviting pedestrian environment.

2. Landscaping

Integrating landscaping elements into urban environments can be an effective strategy for mitigating the channeling effect. Well-placed trees, shrubs, and hedges can act as natural windbreaks, reducing street-level wind velocities and creating more pleasant pedestrian spaces.

Key points to consider:

• Strategically plant trees, shrubs, and hedges to serve as windbreaks.
• Focus on areas prone to wind acceleration, such as open spaces or along streets.
• Choose wind-resistant plant species for effective wind barrier creation.

An example of this concept is shown below, using a tree line and bordering shrubbery to break the wind’s path.

In our design for the street corner, we strategically incorporate a lush arrangement of trees and shrubs to mitigate the channeling effect and improve pedestrian wind comfort effectively. Placed on the windward side of the corner, these green elements act as natural windbreaks, persuading the airflow up and over the tree line. As the prevailing wind from the southwest encounters this green barrier, it is deflected and forced to rise above the tree canopy, preventing it from being channeled and intensified between the buildings at ground level.

This strategic placement of trees and shrubs helps disperse the wind more evenly, reducing wind speeds and creating a more tranquil environment for pedestrians. The greenery contributes to mitigating the channeling effect and enhances the aesthetics and sustainability of the urban landscape, providing a serene and inviting space for people to enjoy.

3. Street Furniture and Structures

Street furniture and structures can be strategically positioned to disrupt wind flow and provide sheltered areas for pedestrians. By incorporating these elements, urban environments can minimize the impact of the channeling effect and enhance pedestrian comfort.

Key points to consider:

• To disrupt wind flow, install street furniture like benches, planters, or bollards.
• Design wind baffles, fences, or deflectors to redirect wind and reduce its impact.
• Consider the placement of bus shelters, kiosks, or urban elements as windbreaks.

In the illustrating example, we put a concrete sculpture in the corner of the park that acts not only as a sitting area and a sound barrier to the road but also as a wind deflector. A pedestrian footbridge is also introduced with mounted traffic signage.

The strategic introduction of a concrete sculpture acting as a wind deflector and a pedestrian footbridge with mounted traffic signage in our street corner scenario mitigates the channeling effect and improves pedestrian wind comfort.

Utilizing Computational Fluid Dynamics (CFD) analysis, we observe the comfort plots revealing reduced wind discomfort and gusts near the corner, thanks to the sculpture’s wind redirection capabilities. The footbridge further enhances wind deflection, resulting in a noticeable decrease in wind velocities in the pedestrian zone. This technical mitigation approach creates a more tranquil and inviting urban space, providing pedestrians with a comfortable environment to enjoy their surroundings, even in wind-prone conditions.

4. Urban Layout and Planning

Effective urban layout and planning can help alleviate the channeling effect and create more comfortable pedestrian spaces. By considering the arrangement of streets, buildings, and open spaces, planners can promote better airflow and reduce wind-related discomfort.

Key points to consider:

• Design a well-organized street network with curved or staggered layouts.
• Incorporate open spaces, plazas, and squares strategically for wind dissipation.

This time, to demonstrate layout and planning, we split the building into two, with one smaller building on the corner, and made the larger building miss the channeling corner, ensuring the pair maintained the same approximate floor space.

In the split site layout, the wind can travel through the site, effectively reducing the channeling effect. Additionally, the presence of the smaller building acts as a deflector, guiding the wind upward and over itself. This combined approach proves highly effective in mitigating the noticeable discomfort caused by the channeling effect. As a result, pedestrians experience improved wind comfort in the area, making the urban environment more inviting and enjoyable.

5. Computer Simulations and Wind Studies

Computational Fluid Dynamics (CFD) has emerged as a powerful tool in mitigating the channeling effect (Venturi effect) in urban design. By simulating and analyzing wind flow patterns, pressure distributions, and velocity fields around buildings and street corners, CFD provides invaluable insights into the complex dynamics of wind behavior, enabling designers to optimize mitigation strategies.

One of the key applications of CFD in mitigating the channeling effect is the generation of comfort plots or comfort maps. These visual representations offer a comprehensive view of the impact of wind on pedestrian comfort in a designated area. By analyzing comfort plots, designers can identify zones where wind intensification occurs, leading to uncomfortable conditions for pedestrians. This information allows for the strategic placement of windbreaks, barriers, and other street furniture objects to disperse wind flow and create more comfortable pedestrian spaces.

In addition to comfort plots, CFD simulations provide accurate wind speed data. By understanding wind speeds in different areas, designers can pinpoint locations where wind velocities are particularly high due to channeling. Armed with this knowledge, they can implement architectural adjustments, such as building orientation, shape modifications, or adding wind deflectors, to mitigate the intensified wind flow and reduce wind speeds at ground level.

One of the key advantages of using CFD in early-stage urban design is the ability to optimize and retest mitigation strategies before physical construction begins. CFD simulations allow designers to explore various design scenarios and test different wind mitigation measures virtually. This iterative approach enables them to fine-tune and refine their designs for optimal wind comfort while reducing the potential costs of implementing changes at later stages.

Overall, CFD plays a crucial role in the mitigation of the channeling effect, providing designers with a detailed understanding of wind behavior and its impact on pedestrian comfort. By utilizing comfort plots, wind speed data, and the ability to optimize and retest designs, CFD empowers designers to create more wind-resilient and pedestrian-friendly urban environments from the early stages of planning, enhancing the overall livability and sustainability of our cities.

Conclusion

In conclusion, our exploration of mitigating the channeling effect in urban design has revealed a wealth of strategies to enhance pedestrian wind comfort. By leveraging innovative approaches, such as carefully oriented building designs, windbreaks, and strategic site layouts, we can effectively disperse wind flow and minimize the channeling effect’s impact. Utilizing Computational Fluid Dynamics (CFD) analysis and comfort plots, we gain valuable insights into wind behavior, allowing us to design more harmonious and people-centric urban spaces.

Through the incorporation of greenery, sculptures, footbridges, and other street furniture, we create multifunctional elements that not only beautify the landscape but also act as wind deflectors and barriers. The successful integration of these technical interventions results in significant reductions in wind speeds and turbulence, leading to more pleasant and comfortable environments for pedestrians.

As cities continue to evolve and urban spaces become more dynamic, addressing wind-related challenges becomes a crucial aspect of designing inclusive and enjoyable environments. By embracing these strategies and merging artistic vision with scientific analysis, we can shape cities that thrive in harmony with nature, providing optimal wind comfort and ensuring the well-being of their inhabitants.

In our pursuit of better urban living, the mitigation of the channeling effect stands as a testament to the powerful interplay between design ingenuity, technological advancements, and the aspiration to create sustainable, vibrant, and welcoming cities for generations to come. Together, let us continue this journey towards wind-resilient, pedestrian-friendly urban landscapes that celebrate both form and function, enriching our lives as we traverse the bustling city streets with comfort and ease.

The post Mitigate Channeling Effect: 5 Strategies for Enhancing Pedestrian Wind Comfort appeared first on SimScale.

SimScale is a cloud-native simulation and analysis platform accessed via a web browser. Users can instantly access a full-fledged HPC-powered simulation platform from a PC, laptop, or tablet​, ​with access to simulation features, learning resources, and an international community of more than 400K ​engineers​, including architects, urban designers, and engineers.

NVIDIA Omniverse is an extensible platform for virtual collaboration and real-time, physically accurate simulation. Creators, designers, researchers, and engineers can connect tools, assets, and projects to collaborate in a shared virtual space. Developers and software providers can also build and sell Omniverse extensions, applications, connectors, and microservices on the Omniverse platform to expand its functionality.

NVIDIA Omniverse SimScale Converter Extension: Seamlessly Export Scenes and Results Between Tools

The NVIDIA Omniverse SimScale Converter Extension is a powerful tool that allows architects and computational designers and users of the NVIDIA Omniverse tool to seamlessly export scenes from Omniverse to SimScale and bring back the results into Omniverse. This can be a valuable asset for a variety of projects, as it allows users to quickly and easily iterate on designs and test different scenarios.

To use the extension, simply upload your USD prims as models to SimScale. SimScale will then run a computational fluid dynamics (CFD) simulation on your model and return the results back to Omniverse. The results can then be visualized and analyzed in Omniverse, allowing users to make informed decisions about their design. The extension currently supports two types of simulations: pedestrian wind comfort and incompressible LBM (Lattice Boltzmann method). Pedestrian wind comfort simulations can be used to assess how comfortable it would be for pedestrians to walk through a particular area, while incompressible LBM simulations can be used to analyze the flow of fluids around a solid object, in other words building aerodynamics such as evaluating high winds, cornering effects, wind acceleration between spaces, etc.

In the future, the extension is expected to support additional simulation types and CAD formats. This will make it even more versatile and useful for a wider range of projects. Here are some specific examples of how the NVIDIA Omniverse SimScale Converter Extension can be used by architects and users of the NVIDIA Omniverse tool:

• An urban designer might use SimScale and Omniverse to evaluate the wind comfort around an existing building and proposed new development for planning permits.
• An architect could use the extension to simulate the airflow around a building to ensure that it is safe and comfortable for pedestrians.
• A designer could use the extension to simulate the performance of different types of trees, vegetation, landscaping, and street furniture and their impacts on site conditions.

For more information about the NVIDIA Omniverse SimScale Converter Extension, you may find explore the corresponding SimScale Coverter Extension documentation.

The Rise of CFD for Urban Design

Microclimate simulation using computational fluid dynamics (CFD) is a growing requirement for many types of buildings and developments. Complex building physics is needed to design and validate advanced net-zero and well-being requirements of modern building codes and rating systems. It is also necessary in order to supplement or even obviate the need for expensive wind tunnel testing. Using traditional desktop modeling tools requires too much computational resources and time to get meaningful results and prohibits the use of simulation at the early design stages as an iterative design tool.

Architects and engineers can benefit from fast and accurate design simulation using SimScale, accessed from a web browser. With no hardware setup or costs, SimScale allows designers to quickly access powerful simulation capabilities and perform multiple analyses using a single CAD model to understand:

• Pedestrian wind comfort criteria
• Wind safety modeling
• Building aerodynamics for urban design
• The use of mitigative measures such as windscreens, canopies, and vegetation

One of the often-most quoted advantages of using SimScale is the lattice Boltzmann method (LBM) integrated solver, which has extremely robust CAD handling features, meaning the simulation is indifferent to complex CAD (including terrain) and requires no geometry simplification to get the simulations going. It is this very solver that connects to Omniverse giving architects and designers the perfect combination of fast and accurate simulations coupled with compelling and powerful visualizations.

On-Demand Webinar

Watch this on-demand webinar to learn more about how to seamlessly export scenes and simulation results between NVIDIA Omniverse and SimScale and build advanced CFD workflows for your architectural design projects.

The post Wind Simulation in NVIDIA Omniverse™ appeared first on SimScale.

All the CFD simulations used in this post are publicly available here.

Understanding the Cornering Effect

To effectively mitigate the cornering effect and enhance pedestrian wind comfort, it is essential to comprehend the underlying dynamics of wind behavior at street corners and intersections. Wind flow at corners is influenced by various factors, including building geometry, street alignment, and surrounding urban morphology. By understanding these factors, we can gain valuable insights into how wind interacts with the built environment, leading to improved design strategies.

Wind Flow Patterns and Pressure Distribution

At street corners, the wind encounters changes in direction and flow patterns, resulting in accelerated airflow and pressure variations. A key aspect to grasp is the creation of a wind vortex, where the wind wraps around the corner, generating intense gusts. Visualizing these wind flow patterns is crucial to understanding the specific areas where the cornering effect manifests.

The illustration above shows how a building’s sharp edge causes the flow to separate around the corner, and if the building is long enough, re-attach to its wall. A rotation in the flow is formed between those two points, often called the corner vortex. The stream of wind separating around the corner is strong, whereas the vortex core tends to be slower.

Recognising the Cornering Effect

One of the most effective ways to identify and analyze the cornering effect is through the use of Computational Fluid Dynamics (CFD). This powerful tool allows engineers and designers to simulate and visualize wind flow patterns, pressure distributions, and velocity fields around buildings and street corners. By harnessing the capabilities of CFD, designers and engineers can gain valuable insights into the complex dynamics of the cornering effect, facilitating the development of targeted mitigation strategies. Join us as we explore how CFD empowers us to unravel the intricacies of wind behavior, paving the way for enhanced urban design and improved pedestrian wind comfort.

Comfort plot

Comfort plots generated by CFD tools provide a visual representation of the impact of the cornering effect on pedestrian comfort. When analyzing comfort plots to identify the cornering effect, focus on areas where pedestrian activities such as walking or uncomfortable exist, indicating intensified wind and gusts. These areas are typically found in proximity to the corners of buildings and often exhibit a curved shape aligning with the wind flow direction.

The corner effect is not always this identifiable in the comfort plot in the presence of more complex urban environments. Therefore, when there is an area of discomfort that is in close proximity to the corner as above but more complex in shape, a user should proceed to inspect directional wind results.

Directional Wind Speeds

The prevailing wind direction is crucial in identifying influential corners where the cornering effect significantly impacts pedestrian wind discomfort. When examining comfort plots and wind speeds for the prevailing wind direction, focus on regions that exhibit cornering effect characteristics. These wind direction results are particularly useful for mitigating the cornering effect. By identifying areas with heightened wind speeds and increased pedestrian discomfort aligned with the prevailing wind direction, designers gain valuable insights for implementing targeted measures to improve pedestrian wind comfort in specific wind conditions.

As we can see in the above example, the cornering effect visible in the comfort plot is pronounced when looking at the directional result for the prevailing wind direction, reinforcing what was mentioned above.

5 Strategies for Mitigating the Cornering Effect

Addressing the cornering effect is crucial to improving pedestrian wind comfort in urban environments. By implementing effective strategies, we can optimize the design and layout of streets and buildings to minimize the impact of wind and gusts at corners and intersections. In this section, we explore a range of practical and innovative approaches to mitigate the cornering effect. From urban planning and greenery integration to smart street furniture and building design considerations, these strategies offer insights and solutions to create harmonious and wind-resistant urban spaces. Let’s dive in and discover how we can shape our cities to provide optimal wind comfort for pedestrians.

1. Urban Planning and Street Layout

Urban Planning and Street Layout are essential tools for mitigating the cornering effect and improving pedestrian wind comfort. By strategically designing street orientations, optimizing building placement and configuration, and considering street width and design, urban planners can create environments that minimize wind and turbulence and can enhance the comfort and safety of pedestrians around corners. Through thoughtful urban planning and street layout, cities can foster pedestrian-friendly spaces that effectively address the challenges posed by the cornering effect.

Here are three key areas that can be improved:

• Street Orientation: Aligning streets with the prevailing wind direction can minimize the impact of the cornering effect. By orienting streets parallel to the prevailing wind, the flow of air can be more streamlined, reducing the intensity of wind gusts at street corners.
• Building Placement and Configuration: The arrangement and design of buildings can help mitigate the cornering effect. Placing buildings strategically to create open spaces or courtyards can allow for better wind dispersion and minimize the concentration of wind around corners. Incorporating rounded or chamfered building corners can also help redirect wind and reduce turbulence.
• Street Width and Design: Proper street width and design can influence wind behavior. Wide streets and generous setbacks between buildings can create more open spaces, allowing for better air movement and dispersion of wind. Additionally, strategically using street furniture, landscaping, and other design elements can help create windbreaks and control airflow.

Consider the following example to illustrate the influence of street alignment on mitigating the cornering effect.

In one scenario, the streets are aligned with the prevailing wind direction, but a perpendicular street intersects them, resulting in poor pedestrian comfort, as shown in the wind comfort plot. However, in another scenario with two parallel streets aligned with the prevailing wind, the wind comfort plot demonstrates a significant improvement in pedestrian comfort. The corresponding wind speed plot further supports the benefits of parallel street alignment by showing reduced turbulence and more even wind distribution. These images highlight the importance of avoiding perpendicular street intersections and aligning streets with the prevailing wind to minimize the cornering effect and enhance pedestrian wind comfort in urban environments.

2. Urban Vegetation and Greenery

Urban vegetation and greenery offer multiple benefits in mitigating the cornering effect while providing additional advantages.

Benefits of trees and vegetation for wind mitigation:

• Windbreaks: Well-placed vegetation acts as natural windbreaks, reducing the speed and intensity of wind gusts. Planting trees, shrubs, or hedges strategically near street corners and building edges can create a buffer zone that disrupts and deflects the wind, minimizing its impact on pedestrians.
• Airflow Guidance: Vegetation can help guide and direct airflow in desired directions. By strategically positioning trees and plants, planners can influence the flow of wind, diverting it away from pedestrian areas or promoting more favorable wind patterns that reduce turbulence and discomfort at corners.
• Turbulence Reduction: Vegetation has the ability to break up and dissipate turbulent airflow. When wind encounters vegetation, it creates a complex flow pattern, leading to the dissipation of energy and a reduction in wind turbulence. This can result in smoother airflow around corners, minimizing the adverse effects of the cornering effect on pedestrians.

Some additional benefits we get from trees and vegetation:

• Microclimate Modification: Urban vegetation contributes to the creation of microclimates by providing shade and cooling effects. By reducing the overall temperature in urban spaces, vegetation helps to alleviate thermal discomfort caused by wind chill factors and enhances pedestrian comfort near corners.
• Visual and Psychological Benefits: Apart from its functional benefits, urban vegetation also provides aesthetic and psychological advantages. Green spaces and lush surroundings have a calming effect on individuals, making pedestrian areas more appealing and inviting. This can encourage people to spend more time outdoors and enjoy public spaces, even in wind-prone areas.

Consider the following example that demonstrates the positive impact of placing a tree on a building corner in reducing the cornering effect. By strategically positioning a tree at the corner of a building, the wind dynamics can be significantly altered. The tree acts as a natural windbreak, disrupting the airflow and reducing wind speeds in the immediate vicinity.

This can be observed in the wind comfort plot generated through computational fluid dynamics (CFD), where the presence of the tree shows a notable improvement in pedestrian comfort compared to the scenario without the tree. Additionally, analyzing the wind speed plot derived from CFD reveals how the tree effectively deflects and slows down the wind, creating a more favorable and comfortable environment for pedestrians around the corner of the building. The visual representations provided by these images serve as compelling evidence of how strategic placement of vegetation can mitigate the cornering effect and enhance pedestrian wind comfort in urban settings.

3. Street Furniture and Design

By integrating street furniture and design elements in a thoughtful manner, designers can enhance wind mitigation efforts while simultaneously elevating the visual appeal, functionality, and livability of urban spaces.

Here are a few Street Furniture and Design techniques you can employ to mitigate the cornering effect:

• Wind-Permeable Structures: Incorporate wind-permeable structures such as open grid benches, perforated screens, or lattice structures. These elements allow air to pass through and minimize the creation of turbulent zones. By reducing wind pressure buildup, they help alleviate the cornering effect and improve pedestrian comfort.
• Sheltered Seating Areas: Design seating areas that provide shelter and protection from wind. By strategically placing benches, seating pods, or alcoves in areas shielded from the prevailing wind, pedestrians can find respite from gusts and enjoy comfortable outdoor seating.
• Windbreaks and Canopies: Utilize windbreaks and canopies strategically placed along walkways or near building corners. These structures act as physical barriers to deflect and redirect wind, creating more sheltered and calm areas for pedestrians.

Imagine a bustling urban street where an innovative solution was employed to mitigate the cornering effect and enhance pedestrian wind comfort. At the corner of a building’s windward facade, an advertising billboard was strategically introduced as functional street furniture. Not only does it serve its primary purpose of displaying advertisements, but this intelligently designed billboard also acts as a wind deflector, redirecting the flow of wind upward and away from pedestrians.

Four impactful images provide a visual analysis of the scenario, comparing a baseline scenario with no street furniture to an improved scenario with the introduced advertising billboard. The first image depicts a pedestrian wind comfort plot, revealing discomfort zones near the corner in the baseline scenario. The second image shows the improved scenario with the billboard, demonstrating enhanced pedestrian comfort and improved airflow. The third image illustrates the wind speed distribution in the baseline scenario, highlighting areas of high velocity and turbulence. In contrast, the fourth image displays the transformed wind speed distribution in the improved scenario, with smoother airflow due to the billboard’s presence. These images emphasize the positive impact of street furniture in mitigating the cornering effect, enhancing pedestrian comfort, and reducing turbulence.

4. Building Setbacks and Façade Design

Building setbacks and façade design are crucial considerations in mitigating the cornering effect and enhancing pedestrian wind comfort. By incorporating appropriate setbacks and thoughtful façade design, architects and designers can minimize the impact of wind turbulence and create more comfortable environments for pedestrians. Setbacks provide valuable space between buildings and the street, allowing for improved airflow and reduced wind concentration at corners. Additionally, façade design plays a key role in shaping wind patterns and redirecting airflow, reducing wind pressures and creating sheltered zones. Together, building setbacks and façade design strategies contribute to enhancing pedestrian comfort and fostering pleasant and livable urban spaces.

As a designer, there are several strategies you can employ regarding building setbacks and façade design to mitigate the cornering effect and enhance pedestrian wind comfort:

• Setback Optimization: Consider incorporating appropriate setbacks between buildings and the street to allow for smoother airflow and reduce wind concentration at corners. Strategic placement of buildings can help create sheltered areas and minimize the impact of wind turbulence on pedestrians.
• Façade Openings: Carefully design façade openings such as windows, balconies, or recesses to control airflow. By directing the flow of air around the building and reducing wind pressures, you can create more comfortable spaces for pedestrians. Properly positioned openings can promote natural ventilation while minimizing the effects of the cornering effect.
• Wind-Resistant Materials: Select wind-resistant materials for the façade that can withstand the impact of wind forces. Incorporate design elements that reduce wind loads, such as streamlined shapes, rounded corners, and smooth surfaces. This helps to minimize the creation of vortices and turbulent areas, improving pedestrian comfort.
• Deflection and Diversion: Employ design features such as canopies, awnings, or windbreakers at key locations to deflect or divert wind away from pedestrian areas. These elements can create sheltered zones, reducing wind speeds and providing more comfortable conditions for pedestrians.

Let’s explore an example where a setback was ingeniously employed to divert the flow of wind up and over a building corner, effectively mitigating the cornering effect and enhancing pedestrian wind comfort. In this scenario, the designer strategically incorporated a setback between the building and the adjacent street. By introducing this setback, a space was created that allowed for the redirection of airflow.

As the wind approaches the building, it encounters the setback, which acts as an obstacle and alters the wind’s path. Instead of directly hitting the building corner and creating turbulence, the setback diverts the airflow upwards. This redirection causes the wind to flow over the corner, reducing the wind and turbulence experienced at ground level.

CFD simulations comparing a baseline scenario without a setback and an improved scenario with a setback demonstrate the effectiveness of the design strategy. The pedestrian wind comfort plot for the baseline scenario shows discomfort and increased turbulence near the building corner, while the improved scenario with the setback significantly improves pedestrian comfort. The wind speed plot confirms the reduction in turbulence and cornering effect in the improved scenario compared to the baseline. These results highlight the positive impact of the setback in enhancing pedestrian wind comfort and emphasize the importance of CFD simulations in guiding design decisions.

5. Computer Simulations and Wind Studies

Computer simulations and wind studies are invaluable tools in understanding and mitigating the cornering effect in pedestrian wind comfort. Through advanced computational fluid dynamics (CFD) simulations, engineers and designers can accurately model and analyze airflow patterns around buildings, streets, and urban layouts. These simulations provide insights into wind speed, direction, and turbulence, allowing for the identification of areas prone to the cornering effect. By simulating various design scenarios and evaluating their impact on pedestrian comfort, practitioners can make informed decisions about building placement, street orientation, and the integration of mitigation strategies. Computer simulations and wind studies empower professionals to optimize urban designs, create more comfortable outdoor spaces, and prioritize pedestrian well-being in wind-prone environments.

Conclusion

In conclusion, mitigating the cornering effect in pedestrian wind comfort requires a multifaceted approach that encompasses various strategies and design considerations. By incorporating strategies such as building setbacks, façade design optimization, urban vegetation, and thoughtful street layout, designers and urban planners can create more comfortable and enjoyable environments for pedestrians.

Through the use of computer simulations and wind studies, professionals can gain valuable insights into wind patterns, identify areas prone to the cornering effect, and evaluate the effectiveness of design interventions. These tools enable them to make informed decisions, optimize urban designs, and prioritize pedestrian well-being.

The presented examples highlight the effectiveness of these strategies in mitigating the cornering effect. Whether it’s the redirection of airflow through setback design or the use of vegetation as windbreaks, each strategy contributes to reducing wind pressures, minimizing turbulence, and enhancing pedestrian comfort.

By considering these strategies collectively and tailoring them to specific urban contexts, designers can create harmonious outdoor spaces that not only provide protection from wind discomfort but also foster a sense of place, connectivity, and livability.

In summary, by integrating these strategies into the design process, we can create urban environments that prioritize pedestrian comfort, enhance the quality of outdoor experiences, and promote sustainable and enjoyable cities for all.

The post Mitigate Cornering Effect: 5 Strategies for Pedestrian Wind Comfort appeared first on SimScale.

In this blog post, we want to get you up to date with all of the new key features released in Q1 2023. Let’s dive in!

1. Improved Wind Data for PWC Analysis
2. Humidity Modeling
3. Realizable Turbulence Model
4. Solids included in solar radiation
5. Joule Heating
6. Immersed Boundary Method (IBM) external flow domain flexibility
7. Simplify/heal bodies with Surface Wrapping
8. Multiphase
9. Relative Velocity
10. Boundary condition Visualization Inside 3D Viewer
11. Export result statistics to CSV
12. Teams and Permissions
13. Bilinear elastoplastic material model
14. “Max over Phase” von Mises stress result field for harmonic analysis

1. Improved Wind Data for PWC Analysis

Improved accuracy and global coverage with the new ERA5T dataset, which replaces the previous NEMS30 dataset. Also, the new modal is provided via our connected wind data service partner, meteoblue, and is the most accurate dataset available for wind data. Additionally, we now have the ability to derive seasonal wind roses from the new dataset, which will be coming in future months.

2. Humidity Modeling

Humidity plays a big part in thermal comfort analyses, and SimScale can now account for it.
Humidity modeling can be hugely important to internal thermal comfort studies for identifying where condensation might occur as well as for analyzing indoor environments where tightly controlled humidity levels are critical, such as concert halls, storage facilities, or indoor farming.

3. Realizable Turbulence Model

For urban wind applications, this turbulence model is declared as the preferred one by several best practice guidelines (COST Action 732) as well as wind engineering guidelines, such as the City of London (CoL) Wind Microclimate Guidelines (ref), if a steady-state CFD simulation is run.
The realizable k-epsilon model is now available for the Incompressible analysis type on SimScale within the top-level analysis type settings.

Use Case & Benefits

Urban pollutant dispersion analysis using the Incompressible analysis type on SimScale for enhanced result accuracy compared to the standard k-epsilon turbulence model.

4. Solids included in solar radiation

It is now possible to model solar loads in CHT analyses with models that have both fluids and solids included.

Use Case & Benefits

• Solar radiation can play a large factor in thermal comfort, and the ability to model it with solids included increases the overall simulation accuracy.
• Solid walls at the boundaries of the flow region don’t need to be modeled with specific boundary conditions defining the conductivity and material thickness but can instead be assigned the specific material, and their thermal properties will be correctly accounted for
• Solids inside the fluid domain simply need the correct material assigned.

The current limitation is that the solids in a CHT analysis with solar load can not be semi-transparent, so windows and facade glazings need to be modeled with an appropriate boundary condition.

5. Joule Heating

Q1 sees the release of Joule heating. This works with Direct Current (DC) applications and is integrated into the CHT and IBM analysis types. Applying Joule Heating to a part, or parts will cause them to heat up realistically.

6. Immersed Boundary Method (IBM) external flow domain flexibility

IBM (Immersed Boundary Method) now allows for different external flow domain positions. This means that we can position the test unit on the floor, wall, ceiling, or suspended in the middle.

Use Case & Benefits

Useful for:

• Lighting, as it can be positioned anywhere
• All electronic assemblies as they are often designed with multiple orientations and installation positions in mind

7. Simplify/heal bodies with Surface Wrapping

Parts are sometimes too complex to work with and so can be simplified with Simscale’s CAD tools. This can currently be found under ‘surface wrap’.

• Faulty models can cause meshing problems, and fixing/simplifying parts in advance should avoid this
• Sheet bodies can be difficult to mesh – wrapping them and forming a solid can solve this too

8. Multiphase

One of our highest-requested features is now in production!

This feature introduces a proprietary multiphase capability within SimScale, with industry-validated methods for high accuracy and fast simulation turnaround for rotating equipment, hydraulics, and industrial equipment simulations.

Benefits

• Volume-of-Fluid algorithm with proprietary high-order reconstruction scheme that captures sharp interfaces well
• Comprehensive physics, including heat transfer and surface tension
• Handling of realistic fluid and material properties
• Binary tree-based meshing and automatic local time stepping for proven stability for complicated geometries

Use-Cases

• All types of turbomachinery, rotating equipment & flow control simulations
• Hydraulic engineering / AEC applications (reservoir, dam gate, etc.)
• Industrial mixers, aeration tanks, tank filling simulations
• Marine applications (static ship hydrodynamics, propulsion systems)

9. Relative Velocity

For correct visualization of rotating equipment flow simulations, it is important to show velocity relative to the rotating blades.

Visualizing the relative velocity field in a turbomachine is crucial as it gives designers insight into the nature of flow within the machine. It is used for creating velocity triangles, which help designers estimate the early-stage performance of the rotating geometry.

Highly demanded by our turbomachinery customers, SimScale will now compute and render relative velocity fields through the rotating regions. This field can be visualized as streamlines, vectors, contours, iso-surfaces, or iso-volumes, and will provide our users greater insight into the flow around rotating components.

10. Boundary condition Visualization Inside 3D Viewer

Boundary conditions are now shown inside SimScale! This has been a long time coming, with (believe it or not) years of effort to prepare everything in the background. Now that it is live, we will continue to iterate on it. If you are actively using SimScale, you will see this evolve over the next quarters.

11. Export result statistics to CSV

The ‘Statistics’ panel can now export all of the data points into a CSV file for external processing. This can be hugely useful with models that contain multiple fluid channels like the one shown below.

Use Cases

• Large organizations that need to control access to content internally
• Small organizations that need to organize content more efficiently

Benefits

• Granular access control
• Intuitive data segregation
• Control of sharing of Team content
• All self-managed

12. Teams and Permissions

Members of teams can now have varying levels of access to content contained within a team, and administrators can manage these settings in their dashboard.

Each member can have view, copy, or edit permissions of the teams they belong to. Each team also includes a setting to control with whom content can be shared (to/from a team):

• No sharing
• Share within the Team
• Share with the organization
• Share with anyone

13. Bilinear elastoplastic material model

Users can now apply bi-linear material behavior via a dedicated interface. Young’s Modulus, Yield stress, Ultimate stress, and strain are simple to define. This change improves non-linear simulation robustness.

14. “Max over Phase” von Mises stress result field for harmonic analysis

Von Mises stress is now available for each frequency in harmonic analyses. This means that as well as identifying resonant frequencies, engineers can also ensure that the structure remains within maximum stress safety limits.

Take These New Features for a Spin Yourself 

All of these new features are now live on SimScale. They are really just one browser window away from you! If you wish to try out these new features for yourself and don’t already have a SimScale account then you can easily sign up here for a trial. Please stay tuned for our next quarterly product update.

The post NEW Features: Multiphase, Joule Heating, Humidity Modeling, Boundary Condition Visualization, and More! appeared first on SimScale.

Transient Conjugate Heat Transfer

Transient simulations capture changes over time, where no steady state really exists.

• Components heating or cooling over time
• Fans failing — how long does it take until critical temperatures are reached?

Individual Color Settings for Model Parts

It is now possible to change color settings independently for each part of the simulated model. This improves rendering by allowing users to customize their scene and enhance results visualization over the original model.

Wall Roughness Factor for Subsonic Simulations

It is now possible to add the wall roughness factor for more accurate modeling of wall boundary conditions in Subsonic simulations. For applications such as rotating machinery and flow valves, it is important to model surface roughness in order to accurately assess its influence on flow conditions and calculate pressure rise/drop.

This functionality allows analyzing complex model cases such as:

• Erosion of surfaces due to cavitation or particulate matter 
• Accumulation of particles (debris) on the surfaces 
• Inherent roughness of the material used 
• Manufacturing processes e.g., 3D printing can create uneven surfaces

Stress-strain Mapped from Company Material Library into SimScale

It is now possible to directly use a stress-strain curve from your company material library for structural simulations. This means faster simulation setup times and reduced input errors. Users will no longer need to characterize elastoplastic material behavior and nonlinear materials with data tables and can directly utilize the material behavior available in their company library.

The added value of this functionality is especially useful for:

• Analyzing elastoplastic material behavior of mechanical components
• Simulating fasteners where the stress-strain curve is mapped vs temperature

Thin Section Mesh Refinement for Structural Analysis

Maximize accuracy and solution efficiency by modeling low-thickness parts with second-order hexahedral and prismatic elements using the new ‘thin section mesh refinement‘.

Physical Contact Monitoring

During nonlinear contact simulations, you are now provided with contact monitoring plots keeping you in the loop on contact penetration and solution convergence, giving you confidence and control over your result outputs.

Conformal Meshing for Heat Transfer Analyses

This is the first step in the direction of conformal meshing for all structural analysis which will bring gains in terms of bonded and thermal contact accuracy as well as dramatically improved solution performance thanks to the merging of nodes at contact surfaces.

Non-linear Static Analysis Stability: Automatic Boundary Condition Ramping

Increasing the automation and robustness of nonlinear static analyses. This feature will ramp up constant loads in the background if necessary for a stable solution.

Highlight Minimum and Maximum Values

Highlight the minimum and maximum values for a given result quantity (within Statistics). This is an extremely valuable way for engineers to quickly and precisely view simulation results.

It is especially useful for:

• Locating the maximum stress within a structure to predict the factor of safety
• Identifying the highest displacements within assemblies

Clear Vibration Result Presentation

A number of post-processing improvements have been released to provide intuitive and clear default post-processing for vibration analyses.

• Frequency analysis deformations are now scaled for a perfect fit within the viewer
• Magnitude and phase are now set as default for all result fields in harmonic analysis, providing physically meaningful visualization of complex quantities
• Absolute motion results can now be visualized for harmonic analysis with base excitation allowing direct comparison with physical test data

Improved Robustness for PWC and Incompressible (LBM) via Manual Velocity Scaling

The LBM solver on SimScale used for the Incompressible (LBM) and Pedestrian Wind Comfort analysis, pacefish®, is using an explicit time stepping to solve the transient flow analysis. For some cases where we experience locally very high velocities in automotive aerodynamics or urban wind simulations, the local LBM velocities can surpass the stability cliff of 0.5, leading to divergence. For such cases, we enable an option in the simulation control to manually adjust the velocity scaling factor to a value lower than the default value of 0.1.

Aerodynamic Roughness in PWC and LBM

This feature provides two new input options for Aerodynamic Roughness:

1. Enable the direct definition of “Aerodynamic Roughness”, e.g., z₀= 0.5m to represent a Suburban exposure or z₀ = 1m for an Urban Exposure
2. Alternatively, using an automatic definition “from Exposure”. Here the selected surfaces will get the respective aerodynamic roughness from the exposure category for each individual wind direction assigned

Natural Convection Boundary Condition for Natural Ventilation Cases

Connect outdoor wind simulations with internal, natural convection studies. The natural convection boundary condition takes into account the facade pressure conditions influenced by outdoor wind and surrounding buildings, improving the accuracy of indoor CFD analyses.

The workflow for the natural ventilation boundary condition consists of the following steps:

• Run a Pedestrian Wind Comfort (PWC) study on the building of interest and its surroundings
• Apply the facade pressure results from the previous simulation as reference pressure for the natural ventilation BC in a consecutive indoor analysis

Dashboard Folders and Spaces

• You can now organize your projects into folders
• Companies can also create spaces that give access to limited groups of users

Take These New Features for a Spin Yourself 

All of these new features are now live on SimScale. They are really just one browser window away from you! If you wish to try out these new features for yourself and don’t already have a SimScale account then you can easily sign up here for a trial. Please stay tuned for our next quarterly product update.

The post NEW Features: Wall Roughness Factor, Contact Monitoring, Conformal Meshing, Dashboard Improvements, and More! appeared first on SimScale.

SimScale offers a collaborative simulation platform, where the entire analysis can be shared or even worked on by team members. SimScale works with many common CAD authoring tools such as Rhino®, Revit®, Sketchup, and AutoCAD®, making it convenient to import and edit even complex geometry.

CFD for Building Simulation

One of the major requirements in performing building simulations is to support and handle complex geometries. Often an external wind simulation is based on city-scale models with a high level of detail. Models prepared for architectural designs might contain interferences, gaps, open shells, and in most cases a detailed topography of the terrain. Some models have their roots from direct drone 3D scans and this makes it a cumbersome task to prepare them for traditional simulation tools. With SimScale’s Incompressible (LBM) and Pedestrian Wind Comfort (PWC) analysis, the traditional CAD requirements are largely mitigated. The Lattice Boltzmann method (LBM) solver (pacefish®) within SimScale is specifically designed for such applications with complex geometries. Its unique meshing methodology differs from traditional finite volume meshing, making it a robust approach to handling CAD imperfections with little or minimal manual effort. In addition to the robust CAD handling, pacefish®’s LBM is a GPU-based solver which can easily speed up simulations with large parallelizations. For example, a coarse microclimate study (transient) on a new building development at the center of Rotterdam city takes about 24 minutes to analyze 8 different wind directions. To take a look at the project please refer to our Advanced Tutorial on Pedestrian Wind Comfort.

Although many external building aerodynamics are considered at an early stage where absolute accuracy is not important, it is important to have confidence in the results. To know how SimScale’s external AEC solution performs, please take a look at our validation cases.

When it comes to new building development, or assessing the performance of an existing building, the indoor environment plays a major role. With an increasing number of people spending time indoors, it is important to avoid a lack of fresh air and poor indoor air quality which might lead to health issues. The Health and Safety Executive (HSE) from the government of the UK mentions that occupant comfort is not just a law but is also associated with certain benefits for office workers including improved concentration and better quality of work. With specific regulations in place for work or public spaces, it is critical to analyze the ventilation requirements with different configurations to arrive at an optimal HVAC strategy. SimScale serves as a single platform to perform a broad range of physics. With SimScale’s thermal and heat transfer capabilities, architects and engineers can easily assess the ventilation requirements by testing different strategies including natural or forced ventilation, building fabric performance, or thermal bridging effects. In the next sections, we will be looking at two examples where SimScale was used to predict the microclimate of a residential building and the thermal performance of a building fabric.

Simulating the Microclimate

The following is one such example where we analyze a new low-rise building in the center of Nottingham, UK. The residential building under development has large commercial buildings surrounding it. The goal of this CFD analysis is to predict how the flow around the building affects the surrounding urban environment for wind comfort and in turn the comfort and natural ventilation of the building itself. A detailed wind comfort study is made around the interested building to assess the likely performance of a naturally ventilated ground floor office.

A pedestrian wind comfort analysis is set up using the CAD model of the residential building with its surroundings. To get detailed wind characteristics around the building, 8 wind directions were simulated using the integrated wind data from meteoblue. The influence of the building in the vicinity is assessed using the Lawson LDDC wind comfort criteria. Based on the geographical location of the study, there are specific wind comfort and wind safety criteria to determine if a space is suitable for certain pedestrian activities. A list of default wind comfort criteria available in SimScale can be found in this article.

Wind criteria assessment shows that the area around the new building is well suited for most pedestrian activities. On the other hand, the secondary objective was to determine if the proposed site configuration can affect the ventilation requirements of the building’s ground floor. Wind pressure coefficients are usually used as inputs for simulations involving natural ventilation. Pressure coefficients can be obtained from CFD or wind tunnel tests, particularly in dense urban areas with complex context and topology. Air naturally flows from high pressure to low pressure, and we can use this information at an early stage to understand and control a building’s natural ventilation openings. Pressure coefficients provide an easy way to assess this, where higher values represent high pressure, and lower values represent lower pressure. Natural ventilation can be designed by changing the site layout, building shape, or even the addition of shapes to control flow such as trees and bushes. In addition to the pressure coefficients, the transient velocity and pressure results written out from the simulation can be used to predict the influence of 3D wind effects on ventilation.

Modeling the Indoor Environment

The thermal performance of building fabric has a significant impact on the energy and comfort performance of the building. The following CFD analysis describes the impact of choosing different building fabrics including insulation layers for the walls and window glazing. 

The aim of this study is to quantify the total heat loss from surfaces and rooms in the building to assess the building’s efficiency in regard to the existing and modified building fabric. The considered building space has several HVAC supplies and outlets modeled according to a winter scenario.

A 3D model of a three-story building is analyzed using the robust Conjugate Heat Transfer V2 analysis to determine its thermal efficiency. For demonstration purposes, a sample office room section with an occupant, furniture, and window facing the sun is the focus. The base configuration has specified U values on the walls and roof. The minimum requirements for the insulation are based on the Building Regulations – England. The table below encompasses six different variations in the level of insulation and glazing considered for this study.

The insulation and roof configurations based on the regulations are applied with layer wall thermal inputs in the simulation. Three window panel configurations were used in this study ranging from single to triple glazing with R values of 0.172, 0.833, and 1.429 respectively. The external walls are tested with wood fiber and phenolic foam insulations. The properties of the walls insulation are as follows: 

• Wood Fibre
  • R-Value: 2.95 (K m²/W)

• Phenolic Foam
  • R-value: 4.65 (K m²/W)

One of the key outputs from the simulation is the wall heat flux (W/m²) on the surfaces which gives us the amount of heat loss to predict the efficiency of the insulation layers and window glazing.

The relatively lower thermal conductivity of Phenolic foam provides an excellent insulation character to the walls, thereby restricting the flow of heat into the building. The results from variation 6 with Phenolic insulation on the external walls and an insulated roof leads to a total reduction of heat loss of about 33% when compared to the base configuration. This in turn improves the thermal comfort of the occupants inside the office room. The temperature measurement shows 16.5 °C at the human chest level. 

How Can Architects and Engineers Get Started With Simulation?

SimScale enables architects and engineers to use cloud-native computational fluid dynamics (CFD) simulation to model:

• External wind comfort and safety
• Indoor thermal comfort and overheating
• Ventilation and air quality
• Solar gains and fabric energy efficiency

Designers can benefit from fast and accurate heat loss predictions, as well as the ability to visualize heat conduction through the building envelope, akin to those generated by thermal infrared photography.

Be sure to watch these on-demand webinars to learn more:

Simulating Building Performance

Learn how to simulate microclimate, thermal comfort, fabric energy efficiency, solar gains, and indoor air quality all from your web browser.

Darren Lynch Application Engineer

Fabric First: CFD for Passive Environmental Design

Learn how to model the thermal performance of the building fabric and evaluate energy efficiency options using powerful engineering simulation in the cloud.

Darren Lynch Application Engineer

The post Building Simulation in the Cloud appeared first on SimScale.

As I traveled the city, it really got me thinking about the development process that architects, urban planners, and civil engineers must go through in order to cope with an ever-changing populace and environmental landscape. The reality of man-made climate change has accelerated the need to make more educated, data-driven decisions to drive sustainability and survivability. This is particularly true along coastal areas due to high winds and sea levels, especially during major hurricanes. Computer simulation is playing a major role in informing this early-stage decision-making process and enabling AEC professionals to develop smarter and more efficient cities and structures. 

Urban Microclimate Modeling Using SimScale

For now, we will focus on the problem of dealing with the effects of wind, setting aside water management for a future post. In order to understand the detailed effects of wind on structures and urban areas, the AEC industry has increasingly turned to advanced computational simulation (CFD) tools. Historically, these software packages require a large investment in hardware, licensing, and expert personnel to deploy. SimScale has changed this paradigm by offering an intuitive browser-based platform to conduct high-fidelity wind comfort CFD simulations entirely on the cloud.  

The SimScale platform has been adopted by leading global AEC firms to utilize the Pedestrian Wind Comfort (PWC) approach during early stage design. Learning about your design early rather than later in the cycle and mitigating issues is the objective. Upfront in the process, you have more opportunities to correct problems, but the challenge is often in having realistic data to identify these problems. SimScale PWC modeling can solve this paradox by providing realistic wind behavior in advance.

Our Case: Boston Common Microclimate Simulation

To illustrate how SimScale PWC is used in the early-stage design process, refer to the below Boston city data imported from bostonplans.org. The building of interest is highlighted.

The objective of this early-stage study could be to identify the site layout/orientation, building and feature heights, optimal activity areas based on wind comfort, and problematic or dangerous areas due to high winds.

Thanks to the robustness of the SimScale PWC approach, this geometry did not require any cleaning and is ready to simulate after a small topology extension is applied at the periphery as per our best practices. Because the SimScale PWC solver is based on a fast, cloud GPU method, results for all wind directions can be returned in 1-2 hrs. Additionally, many designs can be tested at once in parallel.  

All of this computational power would be useless if it was not easy for the PWC professional to set up and run. Thankfully, the PWC workflow is tailored and guided for non-expert users, with a simple guided process and advancements such as a built-in wind calculator leveraging data from meteoblue. If you are a more advanced user, the UX does provide access to additional settings and controls to customize your simulation.

So, how do we use our PWC analysis results to drive design decisions?  First and foremost, the PWC analysis determines if a space is suitable for certain activities and displays this data via an aggregated wind comfort criteria plot.

This wind data should be superimposed with the areas where certain activities will be performed (eating, standing, walking, shopping, etc.). The simulation results should then be interrogated to inform what is the root cause of the local wind effects.  The major drivers of urban wind acceleration are:

• Downwash
  • Tall buildings draw fast air from high down to ped level
• Corner Effect
  • Air accelerates around corners
• Channeling Effect
  • “Venturi” effect, where local flow restriction between buildings causes air velocity to increase

Now that cause and effect are understood, all that is left is to propose design changes and mitigation strategies in order to meet your functional requirements. These changes can be virtually iterated on all at once, thanks to the power of SimScale cloud platform.   

In this Boston example, a glass canopy is proposed to deflect the unwanted high-velocity downwash from the larger building that was identified in the baseline PWC analysis. This simple geometry change was made and the case was quickly reevaluated. As seen in the comparative results below, the canopy was effective at reducing the unwanted high winds in the alleyway on the North side of the building, though more iterating is still required to improve the conditions to the East.

Cities Must Quickly Adapt to a Changing Climate

Just as I witnessed in my trip to Charleston, the urgent need for more sustainable, safe, and comfortable urban microclimates is prevalent in cities across the globe. This challenge can be addressed through the use of the accessible flow simulation capabilities of the SimScale platform. Civil engineers, urban development project managers, and architects can easily and quickly implement detailed wind simulation studies to predict and assess wind effects early on in the design phase, well before the validation and construction stages. 

To learn more, watch the Microclimate webinar below:

The post Microclimate Simulation for Architects and Engineers appeared first on SimScale.