'Truck Test' simulation project by mwatkins


I created a new simulation project called 'Truck Test':

self tutorial

More of my public projects can be found here.


Hi @mwatkins

I think you are trying to perform an external flow analysis over the truck geometry. Kindly refer to this project which might be of help to setup the simulation.
If you have any queries please do not hesitate to contact us.

Sam (@sjesu_rajendra)


Hi Sam,

Thanks so much for your note, and you are correct in what I am trying to do. I currently do CAD modeling, and a company that I consult for wants me to do some CFD in the area of trucking.

My background is in Physics, so I conceptually understand CFD and FEA. However, I am new to setting up these problems for solutions on your platform, so a tutorial is helpful.

I chose your product over the standard OpenFOAM platform because your interface reduces my learning curve. Once I can prove my competence in using your platform the company I work with will want me to upgrade to a private/paid account.

Thanks again for your guidance in this area. Mike


Hi Mike @mwatkins,

I took a quick look at your project. This should be rather straightforward to simulate with SimScale - as @sjesu_rajendra wrote, there are many similar projects available. However you’d need to prepare the CAD model a bit more. I noticed that the truck cabin is not watertight. There are open holes close to the frontwheels (see images). This will lead to the fact that the flow will enter the cabin, which would be non-physical.

Hope that helps,




Hi David,

Thanks for your input, but this leads me to a few practice questions about watertightness:

  1. Did you find this gap visually/manually, or is there a more precise method for holes that are too small to see?
  2. I can fill in the larger holes with my CAD software - Fusion 360 - but my attempts to use meshmixer to weld surfaces has been a failure. Im just not used to working with surfaces. My background is in Physics, and I usually develop prototypes as solids and then pull my 2d drawings from that for tech drawings. I acquired this truck drawing from a vendor, and my goal is make modifications to test drag.

Once I solve the watertight issue I look forward to running some practice simulations. Thanks. Mike


Hi Mike @mwatkins,

regarding your questions:

  1. In this case in fact I found it visually. Currently, SimScale does not check for watertightness of geometries but a surface checker is being worked on at the moment to provide more information on how well suited an uploaded model for meshing will be.

  2. From my perspective and without knowing the details of what you intend to do, your workflow makes a lot of sense. There is no need to work on surfaces for the simulation, depending on the specific use case, it might be in the last step but not necessarily all the time. You can simply upload the solid model (ideally as STEP) which will be implicitly watertight and run a sim of it.

Looking forward to seeing your finished simulations. By the way, @ch3316 and me were just discussing on aerodynamics analysis of trucks over here in this thread: Mesh Error - maybe there are some relevant hints for your work.