Week 4 Challenge : CFD Meshing for BMW car

AIM:

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

PROCEDURE:

  To solve the model, first we have to partialise the given model into a symmetrical half portion, which divides the model into a half from top plane axis . After dividing it only half of the model is set for solving for volumetric mesh 

 To solve for volumetric mesh, procedure wise solvings are done which defines 

• TOPOLOGY
• SURFACE MESH 
• VOLUMETRIC MESH 

 TOPOLOGY:

• Topology defines the model with zero single con error and double con error and then triple con error
• It clears the model with arising  errors and solve gemoetrically suitable for meshing 

SURFACE MESH 

•  Solves the mesh on the 2 dimensional plane allowing the  model suitable for 3 dimensional volumetric mesh
• I used tria mesh elements for solving the model with respective given mesh

VOLUMTERIC MESH

• I couldn't use volumetric mesh on the given model as  my system compatiblity is normal 
• Normally after surface mesh volumetric mesh is done by defining the volumes created in model

    I hereby attach my screenshots of solving the model from topology to surface mesh

 

   made a symmetrical model for doing topology and started with headlight section

• Deleted the inner volumes of the headlight section for avoiding any inner volume as the model here meshed is targeted for only a single volume attached with silencer and wheel volumes separately. 

• Grill sections are cleared with single cons and triple cons    

•  In logo sectional area the logo remains common for both the sides , so here the logo part alone is not symmetrified

•  Headlight and rear light sections are cleared with topological errors.

•  Wheel part 

• Rear view mirrors
• In rear view mirror the part separaing the body part with mirror cross sectional area is intersected and a common area of volume is derived to delete and it thereby goes into Body PID.

•  Evaluating errors with geometrical checks

• Intersectional errors are cleared with wheel and body pid wth intersection,cut options in topo mode/ 

PID Assignation is done after topology for identifying the propert of the car so that meshing can be done PID wise for the given sectors in the car 

Reconstruction for mesh is done for solving the indicated quality criteria on the logo PID .This is followed for every PIDs alloted 

LOGO

GRILLS

• meshing the grill PID

WINDOW

• Meshing the window PID

HEADLIGHT

• meshing the headlight PID

TIRES

• meshing the Tire PID

• Only body PID alone left for meshing it.

BODY PID

 Errors arised while solving for the body PID as the perimeter boundary for the body PID was not selected properly and the mesh quality criteria was not correct.

• After meshing the whole part with off 0 elements symmetry is done.

Taking symmetry on the other side after fininsh meshing the whole car PID wise with 0 off elements

• Creating wind tunnel with the help of relative points.

•  BMW m6 car which is surface meshed is inside the Tunnel 

CONCLUSION

  Finally meshed BMW car inside a wind tunnel 

•  ansa file size for solving this came to 300MB which failed to get uploaded in this portal, Ihave attacged a google drive file link which has acess to everyone.

https://drive.google.com/file/d/1zfz65yiy07ZABMnyDk8XY-rqQEm-MppV/view?usp=sharing