Empowering architects with faster and smarter building CFD simulations.

Introduction

The high density of buildings in inner city areas can accelerate wind speeds up to three times the upstream velocity [1]. This creates uncomfortable and hazardous conditions for pedestrians whilst also affecting the safety and thermal comfort of buildings.

Therefore, it has now become essential for architects to understand the behaviour of wind flow through cities. This allows them to not only design buildings that comply with wind regulations but also harness wind through passive strategies that can deliver additional benefits to their clients, such as reducing building energy consumption by 23.6% [2].

In this article we will uncover the daily challenges facing architects and how an automated CFD tool, such as ArchiWind, is the key to unlocking faster and cheaper optimised building designs.

Image: ArchiWind CFD image showing streamlines around a building in an urban environment – needs sourcing. Alt text: ArchiWind CFD simulation with coloured streamlines showing the airflow around a building.

High building density in urban areas can accelerate wind speeds up to three times the upstream velocity

The limitations of current wind analysis workflows

Following the introduction of wind regulations over recent years, architects now need to complete comprehensive wind assessments on their building designs to ensure they pass the necessary wind load criteria. Typically, this is outsourced to environmental consultants who use CFD software to analyse the wind performance of a building for different wind velocities, profiles and speed-up ratios.

‘Architects want to quickly understand if their initial design passes wind tests, so they can start work on the next design iteration,’ highlights, Thomas Michelon, Product Owner of ArchiWind at Nablaflow. ‘The problem is, outsourcing this work means they often have to wait weeks for feedback, and only then can they continue development. Once their next design is ready, the aerodynamics need to be re-assessed, causing even further delays.’

‘These long feedback times limit the number of options architects can explore within project timelines,’ adds Michelon. ‘Also, the feedback typically prioritises wind optimization, without considering other building requirements, making it difficult for architects to balance wind performance with design objectives using these results.’

Article: ArchiWind - from research to commercialization

ArchiWind’s answer to accelerating building CFD

To give the power back to architects, ArchiWind has been developed to simplify and automate this CFD process. This not only achieves faster simulation runtimes but also gives architects the flexibility to run their own CFD wind assessments whenever they need to and at a much lower cost than outsourcing.

Furthermore, to better suit the needs of different stages within the design process, ArchiWind offers architects two types of CFD simulation:

Draft simulations – Preliminary wind analysis that details the main wind patterns and potential issues. Runtime of less than an hour and ideal for volume design work during the initial stages of development.

Detailed simulations – Comprehensive wind analysis that captures complex wind patterns and can serve as proof of compliance. Takes approximately six hours to run and best suited for building permit applications.

How ArchiWind achieves fast CFD runtimes

Both the draft and detailed simulations solve impressively quickly compared to other commercial CFD software, especially considering the large domains involved in modelling the aerodynamics of buildings and their surrounding areas. So how has this been achieved?

ArchiWind automatically post-processes CFD results into visualizations that are easy to understand

‘In general, the CFD process is predominantly the same, no matter what is being simulated,’ explains Michelon. ‘The user uploads a 3D model, selects the required set-up parameters and the software meshes the geometry before simulating the results.’

‘To help streamline each stage of this CFD process, we have implemented a range of automation techniques,’ adds Michelon. ‘For example, the code has been designed to cope with any irregularities found in Revit or Rhino 3D models. So, architects simply choose the relevant settings, upload the 3D model of their building design, surroundings and local terrain, and ArchiWind ensures these geometries are ready to mesh in minutes. This accelerates the set-up phase whilst facilitating robust mesh generation.’

Delivering actionable insights for wind analysis architecture

Once the CFD simulation has completed, the results are automatically post-processed into a variety of interactive 3D visualization including comfort, wind speed, turbulence intensity and wind safety maps. The software also provides guidance on mitigation strategies, so architects not only benefit from accurate and quick CFD results, but also actionable insights which they can then implement.

ArchiWind also suggests mitigation strategies, helping architects turn CFD results into actions

‘You don’t need to be an aerodynamics engineer to interpret or understand the results from ArchiWind,’ says Michelon. ‘This means that any architect can run a simulation, have confidence in the results and then leverage these findings to design more aerodynamic buildings.’

The role of AI in faster CFD simulations

To add an extra layer of speed and accuracy, the developers behind ArchiWind, have been exploring the potential of implementing Artificial Intelligence (AI) within the software. Instead of running a new CFD simulation for each design iteration, one detailed simulation can be used to train an AI model. This AI model then analyses an aerial picture of a wind comfort map and automatically update 2D results as the user iterates the design.one can use AI wind prediction based on a training set of Detailed simulations. The models outputs wind velocity and wind comfort at pedestrian level.

‘This would allow architects to modify their designs directly and get instantaneous results on how their changes effect wind performance, without having to wait for another CFD simulation,’ reveals Michelon. ‘This also gives them the freedom to investigate an unlimited number of design options.’

‘Currently, we are developing plugins for both Revit and Rhino so that this feedback can be directly implemented within these drawing tools as well,’ concludes Michelon. ‘We have all the technical bricks to achieve this, we are just refining how to put them together to deliver the most benefits to architects. But there’s no question, that AI has the potential to change what’s possible with our software, and the CFD industry as a whole.’  

Want to see how easy it is to run a wind assessment in ArchiWind? Click to start your free trial.

References

[1] P.U., G.B., M.G., 2025. Assessing Pedestrian Comfort in Dense Urban Areas Using CFD Simulations: A Study on Wind Angle and Building Height Variations [Online]. Preprints.org.

[2] 2020. Primer for Cool Cities: Reducing Excessive Urban Heat. [Online] Energy Sector Management Assistance Program (ESMAP).