Challenge

Project 1 : CFD Meshing for Tesla Cyber Truck

AIM: CFD Meshing for Tesla Cyber Truck

OBJECTIVE:

To identify all topological clean-up and do geometrical clean-up over entire model.
To create different PIDs and assign it to different parts.
To create surface mesh over model with different Target lengths respective of different parts.
To create a wind tunnel around the tesla truck.

PROCEDURE:

Download the CAD model of tesla truck.
Identify and do topological clean-up for geometry errors.
Then go for geometry checks.
Remove all the geometry errors which are given by geometry checks.
After importing model delete half model and ‘topo’ is applied on it to join the single cons into double and triple con.
Single cons and triple cons are identified and Topo-cleanup is done to patch the open surface and delete unwanted surface.
Topo cleanup for model is done by deleting unnecessary surfaces from model to remove triple cons, delete un-wanted hot points, and single cons are removed by patching the surfaces using New-Coons/Fitted options
Topo cleanup of door handle includes removing triple cons by deleting the unwanted surfaces.
Geometric checks are performed to have no single cons present in the model and possible triple cons are removed by deleting it using universal delete option.
PID’s are assigned using the PID manager for all parts in the body.
Before creating surface mesh the cons and small edges that have length less than minimum mesh length are identified by measuring the distance between cons and solved using ‘cut’ option in order to avoid mesh failing the mesh criteria at this small surfaces.

fig1: PIDs generation

Surface Mesh:

Target lengths for the different parts of a model are as follow:

Individual elements are meshed with respective mesh length with minimum and maximum length.
Surface meshing for tires: Tires are isolated and given a mesh length of 3 mm with minimum and maximum length of 1 mm and 4 mm with triangular elements.
The mesh improvement can be done by using options like Reconstruct, Split, Smooth, Move the grid.
Once the off element’s number boils down to 0 then meshing is done successfully, and similar method is used for other PID’s. The Final Mesh on the half part of Truck is shown in the figure.
Symmetry need to be performed on the other half of car in which the all the components with mesh are copied directly to the other side using Transform option from the top side option list.

Wind Tunnel:

The wind tunnel dimensions are, if x is the length of Truck (5660 mm) then
Front of wind tunnel is 4X (22700 mm) from the truck
Rear of wind tunnel is 6X (33960 mm) from the truck
Top of wind tunnel is 3X (16980 mm) from the truck
Side walls of wind tunnel are at X from the side portion of truck
Bottom of wind tunnel is in close proximity of wheels
Points are created by using ‘Relative option’ in points of Topo Deck.
Topo Deck- points- relative –points- select points. After the points are created join these points from bottom plane by ‘create curves’
Once the curves are created for top and bottom then create a surface with help of ‘New’ option in ‘faces’
Topo – Faces- New-Fitted-will open PID manager window- create new PID-double click on it to create surface on it.
As the analysis of what happens over the surfaces of car is of importance so the bottom of wind tunnel should have good resolution as compared to top portion as it relatively at larger distance than bottom. So mesh length of 40 is taken at bottom and 200 for top portion.
As the front and rear of car are connected with the top and bottom surfaces then the mesh length for this surfaces should vary from 40 to 200 from bottom to top portion. This gradual variation can be achieved using ‘Spacing’ option from the perimeters section of Mesh deck.
Perimeters-Spacing –Geometric – factor of 1.1 and d-min of 40, d-limit of 200 successful application of this will be indicated by upward pointing arrows.

Fig2: Tunnel Mesh with Truck

Conclusion:

All parts were surface meshed including wind tunnel surface. Also For Volumetric mesh unmeshed volumes are auto detected.

Ship work like this
in your own course.