Week 4 Challenge : CFD Meshing for BMW car

Aim:

• For the given model, check and solve all geometrical errors on half portion and Assign appropriate PIDs. Perform meshing with the given Target length and element Quality criteria. After meshing the half model, Do symmetry to the other side.

1. Type : Tria
2. Body - 3 mm
3. Lights - 4 mm
4. Grills - 1 mm
5. Rims and Tyres - 2 mm
6. Optical Rear view mirror - 2 mm
7. Window - 2 mm
8. Silencer - 3 mm
9. Logo - 1 mm

ANSA File:

https://drive.google.com/file/d/1e6CeujyPzwrWX00NaZOhv_EAugSPTdI5/view?usp=sharing

Procedure:

• Open ANSA import the BMW geometry in main window.

• Given model is symmetry so we can delete half side of the geometry clear the error in one side of the goeometry and perform surface mesh and then mirror them by using symmetry option.

• After deleting the one side of the geometry go to checks-> geometry to identify the errors like single cons and triple cons.

• Isolate the model part by part to clean up the geometry using TOPO. Delete unwanted single cons, triple cons and overslap surfaces and create new surfaces.
• We can delete improper surface and create proper surfaces. And Assign the appropriate PIDs.

• After clear all the errors in the model go to quality criteria change the quality criteria based on the mesh size and change the mesh parameter as well.
• Isolate the every PIDs one by one and do mesh using spot mesh. Use hidden option to identify the off elements.
• Some of the off elements can be automatically solved by using reconstruct option. Remaining off elements should be solved by manual by check the geometry and measure the double cons in the geometry wheather the distance under the quality criteria or not.
• If the off elements present even there is no error in the geometry then use move tool to solve those off elements. Repeat the same procedure for all PIDs and generate the surface mesh.

Surface Mesh:

 

Mesh Size = 1mm

PIDs: Grills, Logo

Quality Criteria:

Mesh Parameter:

Mesh:

Mesh Size = 2mm

PIDs: Rims, Tyres, Window, Optical Rear view mirror

Quality Criteria:

Mesh Parameter:

Mesh:

Mesh Size = 4mm

PIDs: Lights

Quality Criteria:

Mesh Parameter:

Mesh:

 

Mesh Size = 3mm

PIDs: Silencer, Body

Quality Criteria:

Mesh Parameter:

Mesh:

 

• After the mesh generation copy and mirror the half side of the geometry by using translate option-Symmetry

• After the mesh generation wind tunnel need to be created. Create a point in the bottom centre of the model take that point as a reference measure the geometry and create more points based on the measurement.
• Then create PIDs and assign them for wind tunnel. After that go to the Quality criteria change it based on the mesh size of the top and bootom surfaces of wind tunnel. Do surface mesh and check the off elements.

• After that do surface mesh for sides of the wind tunnel based on the top and bottom surfaces the mesh size will increase continuiously from bottom surface mesh size to top surface mesh size by using spcing option.

Wind Tunnel:

 

Surface mesh:

 

• After the surface mesh go to volumetric mesh define the volumes. And delete unwanted volumes.

 

" I can't upload ANSA file in challenge panel so I upload a file using drive link above in the report"