Purpose-built CFD

Purpose-built CFD

Tired of spending hours configuring CFD simulations and days interpreting the results? So were we.

The evolution of CFD

In the specialized domain of wind engineering, computational fluid dynamics (CFD) has long been viewed as a useful tool for early and mid-stage design analysis. Unfortunately, the complexity of simulation tools, the cost of computation, the lengthy delays before simulations are complete, and the expertise needed to interpret the results have largely restricted the application of CFD to high-budget projects at large architecture and engineering firms.

However, the early stages of the design process should be a time of iterative exploration and experimentation—and CFD should be a practical and cost-effective option for every project at every firm.

To address these needs, we created a specially tuned CFD-powered wind simulation engine that’s faster than alternatives, easier to use and to understand, and much more affordable.

Intended to help refine designs after they’ve been validated with our AI-based simulation engine but before more detailed wind engineering and microclimate analysis begins, this engine is:

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Purpose-built for urban analysis

Over the course of ten years, RWDI’s specialists modified the RANS approach to meet the specific needs of urban microclimate analysis

Validated against wind tunnel tests

Decades of RWDI wind tunnel tests and in-house climate expertise directed and validated the engine’s performance

Relied upon within RWDI every day

The engine exists within a continuum of simulation tools employed by RWDI’s microclimate and building performance teams

Ready to see Orbital Stack’s powerful CFD-based simulation in action?

Unique Expertise. Unique Capabilities.

Using CFD for wind simulation and analysis isn’t new, so what makes Orbital Stack different?

Orbital Stack is part of RWDI Ventures and is backed by RWDI—the global leaders in understanding the complexities of how the localized environment and climate impacts large-scale structures (and vice versa).

The RWDI Advantage

Over the course of 10 years, RWDI’s experts have fine tuned a collection of simulation tools that meets the unique requirements of projects throughout the various phases of a project design lifecycle.  Orbital Stack’s simulation environment has benefitted from all of this R&D, and today delivers microclimate analysis at many levels of fidelity: 

A Continuum of Offerings

Orbital Stack supports a continuum of design support, from do-it-yourself simulation in Concept Design to high precision analysis and city submission support guided by RWDI experts in Schematic Design and later.

Design & Iterate

For truly rapid massing iteration during Competition, Feasibility, and Concept Design, speed is prioritized.  To meet these requirements, Orbital Stack offers its AI solution  → this engine is available through Orbital Stack [Learn more]

Refine & Pitch

For full-featured refinement and testing of design ideas in these early stages, speed is still important, but additional insights are needed to fully understand and relay the story. To strike this balance, RWDI’s engineers developed a modified Reynolds Average Navier-Stokes (RANS) simulation engine. This solution supports a wide variety of geometries as well as an ability to model some porous elements. This option leverages the speed and affordability of RANS while providing more accurate results than out-of-the-box solutions → this is the CFD engine offered directly by Orbital Stack


In Schematic Design, when looking for detailed design insights and for many city submissions, precision becomes increasingly important.   For this stage, the Orbital Stack and RWDI teams employ higher fidelity meshing and sometimes a combination of modified RANS and Large Eddy Simulations (LES) for the highest accuracy possible.  But precision doesn’t come from CFD alone; more wind directions are simulated, RWDI leverages its own carefully developed climate database, and RWDI’s expert modeling team meticulously researches and builds surrounding context models and refines study model detail to ensure that all aspects of the evaluation meet the exacting needs of this stage in the project lifecycle. (available only through RWDI consulting engagements – simulated and delivered in Orbital Stack)


For the utmost precision in Detailed Design and Construction Document phases, and for large signature projects, Orbital Stack exclusively applies Large Eddy Simulations (LES) achieving a level of accuracy comparable to the wind tunnels. Combined with all the care and attention of the previous stage, this approach has the advantage of being able to delve into finer details of the design, fully visualize flow dynamics, and explore a wide variety of mitigation measures. (available only through RWDI consulting engagements – simulated and delivered in Orbital Stack)

Want to learn even more about Orbital Stack CFD simulation? Visit our Help section
Want to learn even more about Orbital Stack CFD simulation? Visit our Help section

Ready to power your designs with Orbital Stack?