Save weeks! Run aerodynamic simulations on open surface models.

In this video, we’ll be looking at how to speed up the aerodynamic design process by working directly with open surface models! Solid vs Surface models First a few words on solid versus surface models. In engineering, most 3D models are designed just like they are machined in real life: you start from a solid block and take away the excess material until you have the desired shape. It’s still solid on the inside and there are no gaps between the different outside surfaces. In design or styling, however, 3d models are often built as a combination of complex surfaces: you start for example from a simple rectangular plane, which has two sides. Then you start pushing & pulling the different vertices on that plane until the shape looks good. To obtain the full 3D model, multiple surfaces are put together, sometimes overlapping, sometimes with gaps in between. Watertight models Now when it comes to aerodynamics simulations, it is typically required to work away all the gaps & interferences, to obtain something that is called a watertight or manifold 3D model. In case of surface models, this often means weeks of model fixing to obtain a 3D file that is ready for simulation. A trick to avoid remodeling is to use a wrapping method, which will literally wrap a closed surface around your model. But this can be quite tricky, as you may end up losing small details or closing holes & small gaps that weren’t supposed to be closed, like ventilation holes in a helmet for example. Algorithms The only proper way to avoid risky wrapping methods or weeks of remodeling is to accept the surface models as they are by treating every surface like a wall on both sides. That’s exactly what we do at AirShaper – we tuned our algorithms for months to make them work directly with open surface models. Let me show you an example of how this speeds up the aerodynamic design process:   In Practice Auto Access is a company that develops & installs auto accessories, like for example hardtops for pickup trucks. In the light of more demanding emission regulations, they asked us to assess the impact on fuel consumption of adding a hard top to the Nissan NP300 pickup truck. As you can imagine, Nissan doesn’t simply hand out their confidential 3D data. So instead we turned to a professional website for 3D car models. And as you may have guessed, these are all surface models with plenty of gaps and holes. The results So instead of closing all these holes, which would have required more budget and time, we just uploaded the model straight into AirShaper. Every surface was treated as a real wall on both sides. And although air leaked to the inside in some locations, these static pockets of air didn’t affect the overall behavior of the flow. The result? Just a day after obtaining the 3D model, we were looking at the aerodynamic report. And the best news? Adding a hardtop to the Nissan NP300 doesn’t increase fuel consumption! So that was it for this video, if you liked it, please click the like button below and don’t forget to leave your comments! ----------------------------------------------------------------------------------------------------------- Wouter Remmerie Wouter is the Founder of AirShaper, an online, virtual wind tunnel. With this tool and these videos, we want to make aerodynamics accessible to everyone! Interested in more content like this on the field of aerodynamics? Make sure to click that subscribe button, we post new videos every week! Looking for a way to test your Aerodynamics projects without all the hassle and the huge costs coming with it? Check out https://www.AirShaper.com and see how easy it can be!

Supported by

  • openfoam-logo
  • liso-logo
  • imec
  • start-it-kbc

Code contributions by

  • KU Leuven
  • Inholland
  • Linkoping University