Project 1 : CFD Meshing for Tesla Cyber Truck

AIM
For the given model of tesla's Cyber truck, check and solve all geometrical errors and Assign appropriate PIDs. Perform meshing with the suitable Target length and element Quality criteria and also create a wind tunnel and perform volumetric mesh.

STEPS:

1. Import the CAD model
2. Display setup
3. Geometry check-up
4. Creating the PIDs
5. Defining the Element size or length
6. selection of meshing type

Objective:

• 
  Target lengths for the different parts of a model can be decided by your own.
• Finer mesh will give good results and will compromise with the longest processing time Meshing Wind tunnel volume with tetra elements may take upto 2 days of time.
• So that is not compulsory to perform. As this is a major project, It is advisable to mesh that completely by taking some days of time. Write a detailed report for the same.

Procedure:

STEPS TO OPEN A FILE IN ANSA

• Click on File
• Select Open
• Select File (FORMAT .igs/SLDPRT .ansa etc.)
• Click Open
• A translator window appears CLICK OK

Topo/geometry clean-up:

Upload the ANSA file onto the screen to perform topo/clean and meshing in the later stages.

• Go to mesh
• choose the length
• enter 1 mm under perimeters to smoothen the sharp curves of the car
• give it a fine look.

As the part gets opened in ANSA, firstly it is in wire mode and in entity mode, for desirable visualization we have to change it to shadow mode (It is the visualisation of the part in solid 3D) and the ENT Mode to PID Mode.

As we change it to PID Mode we need to change the colour of the edges in model for desirable visualization as for this we need to follow the following steps:

Steps To Change The Colour Of The Edges In The Model

• Go to Quality criteria option (F11)
• Select the tab Presentation Parameter
• Under visualisation option select Draw CONS in PID
• Click Apply then click on ok.(Now the edges will be in yellow colour ).

Checking The Geometry of the Model

• Goto checks option
• Select Geometry
• An information box will appear
• Click on execute to see the error though it should show no geometrical error for perfect meshing .

Since the car is symmetric from the middle to any end, we can delete one side of the car and perform the necessary operations on the car and use the symmetry option to produce the complete car

After checking and performing topo-clean up for the entire half car model. We need to perform geometry checks to find small
cracks are unchecked faces extra which is not good for the geometry, therefore we need to perform checks and clean the geometry accordingly.

Once the geometry is checked and has no errors, we can now assign names to different components using PID.

We can see that the geometry of the car is symmetric hence we edit one-half of the model and mirror it to get a full model. The right side of the model has more errors than the left side hence we delete the right side of the model.

• USING TOOLBAR
• CLICK DELETE
• SELECT THE ONE-HALF
• AND CLICK MIDDLE BUTTON

GEOMETRY CLEAN UP OF GRILLS:

Assigning Property to the model

To assign the property to the model we need to select TOPO MODE (upper right of the menu tool box)

• Go to TOPO MODE
• Under FACES sub-menu
• Select Insert the hot points(shown as Pressure value)

To perform geometry clean up for SIDE GRILL we have to isolate the part and lock it by using NOT mode and LOCK mode

We have to delete the unnecessary surfaces on the grill

Goto FACES > CUT and enable the parametric cut and then cut the fins that are present on the grill

Perform to all fins and remove the unwanted surface

Goto FACES > NEW > COONS /FITTED to join the deleted surfaces by using these options and the geometry clean up is completed

Delete the half part of the car and perform the geometry clean up for the remaining parts

To perform geometry clean up for BOTTOM GRILL we have to isolate the part and lock it by using NOT mode and LOCK mode

Primarily we have to delete the unwanted surfaces by using DELETE option and make sure it is in ENT mode

Goto CONS > PROJECT and project the cons of the grills onto the surface and delete the unwanted surfaces

Sometimes we can create a new surface by deleting the old surface according to our necessity

Goto FACES > NEW > COONS /FITTED to join the deleted surfaces by using these options and the geometry clean up is completed

Perform similar operations on the INTAKE GRILL

Remove the interior extruded surfaces by using the DELETE option

SYMMETRY:

Goto TOPO mode and perform the symmetry operation for the model

First, we have to isolate tires and lock the remaining model

Goto SYMMETRY > COPY and copy the entire model and select the MIRROR 3 POINT PLANE and select three nodes then it replicates the other image

For safety use the TOPO option to make all cons to double cons by selecting the entire model

In order to perform symmetry on the front tire goto POINTS > ON COG to locate the center part of the tire and use undelete option to retrieve some part of the tire and locate the midpoint of other tires

Perform symmetry Operation by copying tire and translation using two nodes

Change the threads on right-side tires using the same option

Surface meshing:

We need to mesh the components individually since the given mesh targets are different for each PID region.
Assign the mesh parameters and quality parameters for each PID accordingly, assigning the correct min and max length will reduce mesh failure and off elements.

Select the MESH module button > parameters > length

Drag the cursor to cover the entire model and click middle mouse butto to give the mesh size as 5mm for entire model

Select Mesh generators > Free mesh and drag the cursor to cover the entire model and click middle mouse button

CREATION OF WIND TUNNEL:

To create the wind tunnel first calculate the length of the car

Then goto > POINTS > NEW and create points in all directions according to the directions of the wind tunnel

Create three nodes that are responsible to draw a plane

Goto surfaces > PLANE and draw a plane using those three nodes and replicate the same plane using translation symmetry

Repeat the same procedure for the other two sides

Goto CONS > INTERSECT to intersect all planes and delete the unwanted surfaces

Thus wind tunnel is created and assign PID's to differentiate INLET and OUTLET

The link for the meshed model can be found here

https://drive.google.com/file/d/1qW9esPZcu6xDCrJAwe_FDXAEXS6q_wTG/view?usp=sharing

Conclusion:

Cybertruck car model is topo-cleaned and surface meshed appropriately.
The wind tunnel is created and the surface meshed with reference to the car model size. Different volumes of the car model is created since the tires are not connected to the car body.
Single volume is created of the car body so that it can be avoided at one go when creating a volumetric mesh.
Required physics tests can be performed on the wind tunnel volume model after volumetric meshing successfully.