Project 1 : CFD Meshing for Tesla Cyber Truck
ADVANCED CFD MESHING OF THE TESLA CYBER TRUCK
l. OBJECTIVE
1. Geometry Clean-up of the model
2. Generation of surface mesh on the model.
3. Analyze and correct the quality of the mesh.
4. Setting up a wind tunnel around the car.
ll. METHODOLOGY
A. Part 1 - Cleaning all the topo errors and assigning the parts and the PIDs
1. Initial Geometry
The initial geometry is as shown in the figure. We need to clean the given geometry and generate a surface mesh.
2. Topo Clean-up
Perform the face topo clean-up as the model have only single cons, those single cons are converted into double cons
2.1. Splitting the model
As the model is symmetric, split the model in half using a single plane cut option in the faces, two points from the center of the car are selected to create a cut plane to delete the other half of the model.
2.2. Eliminating Single cons
There are single cons present near the side window and wheel, these can be eliminated by creating new faces
2.3. Eliminating overlapped surfaces and creating trunk region
3. Properties IDs
The parts of the model are segregated under different PIDs by naming them accordingly using the Properties tab.
B. Part 2 - Generating A surface mesh on the truck body
The mesh parameters are set and the mesh is generated using the "Spot Mesh" tool.
1. Length of the Element
The following element sizes are assigned to the model-
1. Body - 5 mm
2. Tyre - 3 mm
3. Windows - 3 mm
2. Surface Check
The surface check is performed to analyze the quality of the surface. Edges with lengths less than the minimum target length are reduced using the cut option.
2.1. Mesh Quality
The minimum and maximum length of the mesh does not lie in the required range (in this case 0.1 - 8 mm), which results in quality errors. This can be fixed by reconstructing the macros region.
Quality criteria are the same for all the PIDs with different target lengths. A perimeter of 4 mm is given to all the PIDs while meshing.
2.2. Meshing Errors
We shall be considering three errors - Skewness, Min Length & Max Length.
We need to use the best combination of different tools to fix these errors. The most commonly used tools are - MV Surf, Split, Swap, Cut, Reconstruct & Paste.
2.3. Meshed Surface
Finally, after clearing all the quality errors, the surface meshes.
C. Part 3 - Generating the remaining half of the model using the symmetry plane
The other side of the geometry is created by using the "Copy" command. Using the "Copy" command 3 points located on the edge of the symmetry plane are selected and the command is executed.
D. Part 4 - Generating a Wind Tunnel.
1. Dimensions of the Wind Tunnel
Let X - Length of the Car
A. Front of the Car - 4X
B. Rear of the car - 6X
C. Top of the Car - 3X
D. Bottom of the car - Proximity with the tyers
E. From the center plane (Distance from the Left and Right sides) - 1x
In this case, X ≈">≈≈ 5800 mm
A. Front of the Car - 23,200 mm
B. Rear of the car - 34,800 mm
C. Top of the Car - 17,400 mm
D. Bottom of the car - 500 mm
E. From the center plane (Distance from the Left and Right sides) - 5800 mm
Figure - Wind Tunnel
Figure - Car inside the wind tunnel
2. Meshing The Wind Tunnel
A geometric spacing is assigned with a factor of 1.2, with the smaller mesh elements increasing from the bottom to the top. This is because the top of the wind tunnel is less important compared to the bottom. Finally, the wind tunnel has meshed.
Figure - Meshed Wind Tunnel
E. Volumetric Mesh of the Wind Tunnel - Car Volume
Since we are interested only in the volume between the car model and wind tunnel, we can delete other volumes of the car model which is not necessary.
Since performing the volumetric mesh takes 2-3 days, the volumetric mesh is not performed.
lll. CONCLUSIONS
The Tesla CyberTruck Model is cleaned thoroughly and the wind tunnel is set up. The surface mesh is also generated and the quality of the mesh is improved.
lV. ANSA MODEL