Thought Leadership

5 times when choosing CFD for Pedestrian Level Wind Comfort Analysis can make your life easier

2 people looking at orbital stack simulation on computer screen

Wind engineers have two primary tools for modeling winds around buildings: a computational fluid dynamics simulation tool (CFD) and wind tunnel testing (WTT). While there are advantages that each tool offers, different problems and projects will require one approach over the other, or a combination of both depending on the circumstance.  

When determining which simulation tool is best for you, experienced wind engineers will consider the type of building project – such as the building’s complexity, height, location – as well as local or municipal requirements and local climatic conditions. 

Here are the 5 times a CFD approach may be the solution to save you time, money, and make your life easier: 

1. You’re still early in your design process 

wind comfort analysis that’s too narrow in scope or too late in the design cycle continues to be a common—and costly—source of project compromise and delay. One of the advantages of using CFD to model the impacts of wind on pedestrians is that it is a relatively low cost and quick way of assessing the viability of a project early in the design phase. Having preliminary data that suggests positive outcomes of the design on pedestrians, could help make a strong case for the positive impact a building would have on the community. Buildings that will be located in windy locations, such as on coastal sites, in an exposed environment, or in windy cities would benefit from an early stage wind comfort CFD analysis since the potential for negative wind comfort effects can be high, and should be designed for from the beginning. A wind comfort study using CFD would help identify and solve the complex challenges of a design sooner in these scenarios, saving time now and avoiding costly mistakes later.

2. You know that maximizing the use of outdoor space around the building is of utmost importance

Creating a connection between the indoors and outdoors is becoming increasingly critical, and encouraging vibrant outdoor places and spaces paramount. Semi indoor-outdoor spaces, amenity decks, outdoor event areas, pools, terraces and outdoor restaurants need special care in their design because their day-to-day use is so impacted by weather and wind conditions.

thermal comfort simulation

outdoor public space with walkway, plants and loungers

CFD wind comfort studies can inform where to locate these spaces throughout your project site, and to develop wind control strategies to maximize the use of these amenities. CFD is a great tool in this capacity because wind simulations can easily be combined with other climatic factors, such as the sun, temperature, humidity, all of which contribute to the “total thermal comfort” of people. CFD modeling can provide the necessary data to support how a building’s design will create positive outdoor experiences. 

3. You’re exploring and comparing design options

If you have multiple architectural design options or scenarios that you need to evaluate, then the flexibility of a computer simulation through CFD would be an ideal fit. As architects continue to push the boundaries in their quest to deliver ambitious, sustainable, and beautiful designs, the opportunity to compare different design options early in the process is invaluable. Also, a CFD model can help you consider certain types of wind mitigation options. Thanks to the software’s ability to quickly iterate and test multiple design solutions at once, it is a great way to test alternate strategies, designs, and solutions to wind problems in a relatively fast and cost-effective way.

4. You want to visually see how wind is moving around your site and show this to others

wind speed simulation

The funny thing about wind is that it is invisible! And so it can sometimes be a challenge to describe and visualize how wind is interacting with a building. CFD has the ability to bring wind to life, in creating high resolution graphical color outputs in 3-dimensional format, to debunk the mysteries of which path the wind is taking around your site, and what areas it is impacting. Images can be extracted for proposals, design presentations or regulators, and can even be presented in an interactive 3D environment. Really understanding and being able to visualize wind patterns can help anyone understand the basics behind effective wind control.

5. You are required to fulfill an entitlement requirement and submit a wind study in order to meet a regulatory requirement 

If a wind study is a requirement of your project for entitlement purposes, then depending on the particular regional regulations, you may be permitted or required to consider employing CFD for a wind study. Some city guidelines specify the use of CFD as a requirement for project submission and approval, whereas others may require a full wind tunnel test. It is important to know the requirements in the region where you are designing. 

Some requirements can get complex and it’s often best to partner with an engineering consultant, particularly one with extensive experience with both wind tunnel and CFD simulation methods, as they have done this work in the past and can help you navigate the requirements. This is the best way to ensure that your project benefits not only from expert analysis of the CFD simulation results but also the expertise of navigating and meeting municipal guidelines. 

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Ultimately, CFD and a wind tunnel tests both have a role to play in helping developers, architects, and engineers assess wind and environmental impacts.

Of course, not all CFD methods and tools are created equal, and choosing the right software or the right partner is just as important. RWDI uses Orbital Stack, a state-of-the-art, digital-insights tool that leverages the best practices, learnings, and refinements developed and discovered by our own leading engineers over decades. RWDI engineering consultants can help you determine what type of analysis you need— whether it’s a full, in-depth wind-tunnel study, or a high-level analysis with the latest tool in our arsenal to help you with your project—you can be confident that our expertise will help you get the results you need.

Learn more about RWDI's CFD tool