Project 1 : CFD Meshing for Tesla Cyber Truck

 

 

 

Now the error is fixed after creating the surface.

Now delete half part of the cyber truck, so that errors are reduced and we can copy the model by symmetry plane.

First create a cut along the YZ plane which divides the cyber truck into 2 equal halves.

For that select plane cut > single.

Select thee points on the model, and create a plane cut.

We have successfully created a plane cut.

Delete the half side of the Tesla Cyber truck model.

Delete the extra unwanted surfaces.

Now make a cut on this extra surface and delete it.

Geometry after deleteting those extra surfaces.

 

Fix these single CONS.

Isolate the part we working on by using !Not option and selecting the part we working on.

We have sharp edges here at the corner where body connects with windows.

Steps in fixing this error.

1. Delete this surface.

 2.Create a cut, and delete the surface.

 

Delete the extra hotpoint.

Similarly do it on the other side.

Now create a new surface on both the sides.

Now create the surface where there are Red CONS.

Geometry after fixing the Single CONS.

Now fix other visible single CONS.

Fix these two errors by creating the new surface.

Since there are no major errors visible, go for geometry and penetration checks to find the errors which are hidden inside the model.

Perform geometry checks.

We find that there are single CONS present other then at the outer edges where we cut the Model.

Steps in fixing this error:

1. Create a cut and delete the protruding surface.

 

After deleting the extra surface create new surface.

 

 Now check for penetration error.

We have three major penetration error 2 at the wheels and one at the grill region.

Fixing penetration error at the grill:

Intersection errors are occurring at this region.

We can see the intersections, by hiding the front surface using Not option.

Delete the surfaces which are intersecting, make necessary cuts and create new surfaces to fix this error.

Check again for intersection error.

We now fixed the intersection errors at the grill.

Now fix the remaining two intersection errors at the wheel and Rims.

Fixing intersection errors at the wheel and Rims.

Hide the front surface by using Not option.

 

Turn on PID mode.

 

         

We can see there are  two surfaces overlapping which is causing the intersection error.

Delete the extra surfaces.

Now we have single CONS.

Since the resolution is bad here,

Go to mesh  > length > Perimeters

Set perimeter length as 1

Now the resolution is fixed, Create a surface where there are red CONS.

Similarly do it at the other wheel.

Now again check for penetration error.

We have fixed all the penetration errors.

Check for geometry errors.

We have crack between CONS.

This can be easily fixed by using paste option and selecting the single CONS.

Now check again for geometry and intersection errors.

We now fixed all the geometry and intersection errors.

 

ASSIGNING PIDS:

Next step in our process is assigning PIDs.

Create three new PIDs.

Properties > New > SHELL_PROPERTY > Assign name

 

 

Create three PIDs.

• Tyres and Rims
• Windows
• Body

 

Tyres and Rims

 

Windows

 

Body.

 

Delete all other empty PIDS by selecting compress tool.

 

Meshing:

Target lengths:

• Body: 3mm
• Tyres and Rims: 2mm
• Windows: 2mm

Set quality criteria for Skewness, Max length and min length.

Based on Target length the maximum length in meshing is 4 mm and minimum length is 1mm.

We need to set min length in quality criteria less than 1mm and max length grater than 4.

We set:

• Min length: 0.2 mm
• Max length: 5 mm
• Skewness: 0.5
• 

Mesh each PIDs one by one by one.

Since both tyres and windows has same target length we mesh them together

Setting maximum and minimum length for perimeters and macros.

Select Auto CFD and set maximum and minimum length for perimeter and macros.

Perimeters > Spacing > Auto CFD >

 

Since target length is 2 mm give minimum target length as 1mm and maximum target length as 3mm for perimeter and macros.

After creating perimeters and macros, Under mesh generation CFD > visible

 

We have 3298 off elements.

Fix these by Right click on off > improve > Reshape > select edges

After we improve all the off elements are fixed.

Now freeze this Tyres and windows mesh.

Macros > Freeze

 

Meshing the body:

Since target length is 3 mm, give minimum target length as 2mm and maximum target length as 4mm for perimeter and macros.

We have 1775 off elements.

Fix these by Right click on off > improve > Reshape > select edges

Now we have fixed off elements and completed the meshing of all 3 PIDs.

 

 

After completing the meshing of PIDs, Use transform tool to copy the half truck and copy it by selecting symmetry and 3 point plane.

Transform > Copy > Entities > Symmetry > Mirror 3 point plane

 

Tesla cyber truck model after copying.

 

After copying we will have Single CONs.

Fix these errors by creating new surface, and using paste CONS option.

Since we have created new surfaces, we will have few unmeshed surfaces.

After meshing the unmeshed parts.

Check for intersection and geometric error.

Since there are no errors, Now we proceed to wind tunnel.

 

Creating wind tunnel:

Measure the distance between two extreme points on the Tesla cyber truck model.

Let us approximately take car length as 5700 mm.

Select any point on the bottom surface of a model and create a point below it.

Now create point at a 4 times the length of the car from front extreme point.

To create this measure the distance from the bottom point we used to create point to the front extreme point.

We approximately take the distance as 4200 mm

Add this 4200mm to 4*5700

The total distance from the bottom point = 4200 + 4*5700 = 27000 mm

Use this 27000mm as distance from the bottom point to create point at the inlet.

Similarly create points point behind the car at 6x distance from the back extreme points of the model.

To create this measure the distance from the bottom point we used to create point to the back extreme point.

We approximately take the distance as 2200 mm

Add this 2200mm to 6*5700

The total distance from the bottom point = 2200 + 6*5700 =36400 mm

Use this 36400mm as distance from the bottom point to create point at the outlet.

Similarly create side points on both sides of the car at x distance from the side extreme points of the model.

To create this measure the distance from the bottom point we used to create point to the side extreme point

We approximately take the distance as 1000 mm

Add this 1000mm to 5700

The total distance from the bottom point = 1000 + 5700 =5800 mm

Use this 5800mm as distance from the front and back points we created to create points on both the sides.

 

Create a bottom surface using these points.

To create a surface create a curve between these points.

Now create the surface.

To create the top surface measure the distance of the top extreme point on the model from bottom point and add 500mm to it.

After measuring the distance add 5700*3 to it since the top surface is at 3 times the distance from the top extreme point on the model.

We approximately take distance as 2300mm

The total distance from the bottom point = 500 + 2300 + 5700*3 =19900 mm

To create top surface offset bottom surface by 19900 mm

Now create side faces easily by creating new suraces.

Now the wind tunnel is complete.

 

Wind tunnel meshing:

For bottom surface.

Set target length as 20mm

maximum length = 10mm

Minimum length = 30mm

For Top face set target length as 100mm

maximum length = 90mm

Minimum length = 110mm

 

 

For side faces set manual sapcing and set growing mesh.

Set Dstart = 20mm

      Dlimit = 100mm

 To set the growing mesh, Spacing > Manual

 

Complete  wind tunnel mesh:

 

Extracting the volumes:

Define the volumes, delete the inside volumes of Tesla cyber truck and keep the volume between wind tunnel and cyber truck.

Volumes > Define

Keep this volume between car and wind tunnel and delete other 5 volumes:

 

Delete this car volume:

Delete these tire volumes:

 

Volumetric meshing:

Volumetric meshing requires lot of computauional power, since we are doing it on laptop, Processing power isn’t enough to carry out the volumetric meshing. Therefore we are limiting our meshing to surface meshing due to hardware constarints.

 

Results:

• CFD meshing of Tesla Cyber truck is complete.

 

• Number of tri elements in the mesh are : 12010042

 

Learning outcome :

• Geometry clean-up of Tesla Cyber truck CAD model.
• Creating the surface meshing.
• Creating the wind tunnel
• Defining volumes and deleting the unnecessary volume.

 

Tesla Cyber Truck ANSA File : Tesla Cyber Truck CFD meshing file