CFD Meshing for Tesla Cyber Truck

Abstract:

The objective of this project is to create a wind tunnel volumetric mesh for carrying out external flow CFD analysis on a Tesla cyber truck.

The project workflow is as follows:

1. Importing CAD model to ANSA.
2. Checking for topological & geometric errors.
3. Surface clean-up.
4. Assigning PIDs to relevant surfaces.
5. Making wind tunnel geometry around the car model.
6. Surface meshing the body & ensuring quality criteria is met.
7. Performing volumetric mesh on the volume between the car & wind tunnel.

The quality criteria for meshing different parts of the cyber truck are mentioned below

Skewness	0.5
Min. angle quads	45.0
Max angle quads	0.7
Min angle trias	30.0
Max angle trias	0.7
Min length	As per PID
Max length	As per PID

PID	Minimum length (mm)	Maximum length (mm)
Body	1	5
Windows	1	5
Rim and Tyres	2	8
Lights	1	5

Procedure:

1. The imported CAD has some open curves and missing surfaces.
2. The model after using the topology tool.
3. The geometry check shows only single CONS on the model surface which signify open surfaces.
4. The CFD analysis will be done on a cruising vehicle, so it is assumed that the back of the truck is closed for optimal performance. Also remaining single CONS were resolved.
5. The assigned PIDs are:
6. Important vehicle dimensions are shown below.
7. Now, a wind tunnel volume enclosing the vehicle is made. The dimensions of the wind tunnel are as follows. Here L, W & H are vehicle length, width & height:

   Dimension	Length (mm)
   Front	4L
   Rear	6L
   Bottom	0
   Top	3H
   Sides	0.5W

8. The dimensions for WindTunnel were taken with reference to the lowermost point i.e. 500 mm below the vehicle center. Using these dimensions reference points & curves were created. Subsequently, the wind tunnel geometry is completed by patching these surfaces.
9. Assigning PIDs to wind tunnel surfaces.

Meshing

1. Lights
   • Target length: 3 mm
   • Min length: 1 mm
   • Max length: 5 mm
2. Windows
   • Target length: 2 mm
   • Min length: 1 mm
   • Max length: 3 mm
   • Rim and Tyres
     
     • Min length: 2 mm
     • Max length: 8 mm
   • Body
     • Min length: 3 mm
     • Max length: 5 mm