SimScale CAE Forum

Beginner CFD Analysis Mistake


I am currently trying to simulate a vehicle inside of a wind tunnel. I must have done something seriously wrong when creating my mesh, because I cannot see the correct velocity or pressure fields. It’s like the wind tunnel is being considered as the object.

Additionally, when I try to do a particle trace, all of the wind is going around the wind tunnel, instead of through it. What have I done wrong, and can I fix this without having to re-mesh?

Please see the picture I have posted.

Thank you.

Need link to project…

Hey there @wgrobinson1

This is a boundary condition problem. Make sure your velocity inlet is in the correct direction:

(In this case it would be +63.7 in the y direction).

And no, there’s no need to re-mesh. If you have more issues during the simulation, make sure to reach out :wink:



Yep, link works and it is an easy fix as ric points out…

He just went searching for your project, I was too lazy :wink:

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Thanks for the help. I have changed the velocity to be in the y direction, yet still the air continues to flow around the wind tunnel, instead of through it. :thinking:

Yes, that is because you will have to re run the simulation (only the simulation, not the mesh). Changing the boundary conditions won’t change the results of a simulation that has already been run.

The original settings for a simulation are stored here:


I see, thank you so much!!


I do appreciate the help thus far, yet somehow I still cannot see my pressure or velocity fields. I do not understand what I am doing wrong. Is there any way for you to run/see the results of my simulations?

The particle traces are still acting crazy as well… I changed the y velocity to 63 m/s, while x and z values are 0.

No worries :wink:

Remember that, apart from a velocity boundary condition, you have also set a moving wall BC. In this case, the moving wall is in the same direction as the velocity (positive y):

Make sure to doublecheck the boundary conditions before running the simulation. Right now you also have the whole car selected as velocity inlet

You can take a peek at a similar project that I ran some weeks ago if you want:
There should be more cyber truck projects in the public projects section