Week 4 Challenge : CFD Meshing for BMW car

Aim :

To clean up and mesh a computational domain for an external flow analysis of a BMW Car.

Methodology:

1. Firstly delete half of the BMW car model and perform topo cleanup to that half as they are symmetric
2. Secondly perform geometry check for single cons, double cons, overlapped surfaces and bad surfaces and rectify it by using the following tools as shown below.

• Delete: This was used to delete any entity which cause geometrical errors such as overlapping surfaces, Single and Triple cons.
• Extend: This is used to extend single cons to another face.
• Intersect: This is to intersect between two faces.
• New: This can create new faces between coons.
• Curve: To create a curve between two hot points.
• Project: To project a hot point from one edge to another.
• Fill hole: To fill a closed hot of a specified tolerance.
• Cut: To cut a face into parts

B.Creation of Enclosure

The outer domain was created with a width distance of L measured from the both extreme ends, Length of 6L measured from the rear and 3L measured from the front of the tesla truck and the Height of 4L measured from the top. Where L is the length of the cyber truck ~1.3m. It was created with the help of Relative points to define the points and the curves to join the created points and the New option in faces to generate the macros/surfaces.

Assigning PID's

Creation Of Surface Mesh

Logo

Target Length - 1 mm

Minimum length - 0.4 mm

Maximum length - 2mm

Skewness - 0.5

Silencer:

Target Length - 3mm

Minimum length - 2mm

Maximum length - 4mm

Skewness - 0.5

Optical Rear View Mirror

Target Length - 2mm

Minimum length - 1mm

Maximum length - 3mm

Skewness - 0.5

Tyre

Target Length - 2 mm

Minimum length - 1mm

Maximum length - 3mm

Skewness - 0.5

Grills:

Target Length - 1 mm

Minimum length - 0.3 mm

Maximum length - 2 mm

Skewness - 0.5

Lights

Target Length - 4 mm

Minimum length - 2mm

Maximum length - 4mm

Skewness - 0.5

Body

Target Length - 3mm

Minimum length - 1mm

Maximum length - 5mm

Skewness - 0.5

After Mesh

Total number of elements = 10,65,796

For top surface of enclosure :

Minimum length- 95 mm, Maximum Length-105 mm & Skewness - 0.5.

For base surface of enclosure :

Minimum length-15 mm, Maximum Length-25 mm & Skewness - 0.5.

Total number of elements = 3,82,046

Volumetric Mesh

• In volumetric mesh deck using the Auto-Detect feature check for the volumetric errors before proceeding it
• Then using the tetra CFD mesh perform the volumetric mesh since it is time consuming and requires reasonable computational power here we stopped with surface mesh itself.

File : https://drive.google.com/file/d/1SpRoA2Zx1gA5e2n2ThJvyake73rx7c0y/view?usp=sharing