Week 4 Challenge : CFD Meshing for BMW car

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, to do symmetry to the other side.

Procudrure: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, to do symmetry to the other side.

Learning Outcomes

• Advanced Topology cleanup to define volumes.
• Variable Surface meshing part by part
• Solving quality failed elements as per Quality criteria
• Symmetry operation for surface and mesh elements
• Wind Tunnel Creation
• CFD Meshing for Wind tunnel

Methdology:

Step1 : Delete symmetry of given model

Deleting the symmetric part of car to ease the proseses

Step2:Topo cleanup

Resolution of given model is to be set

Resolution of given model is not proper

going to settings , setting the resolution as needed

as we can observe model the log of BMW is changeing from sharp edges to curve

a.moving to grid for to topo clean up

for above image we can observe that extra cons creat extra volume we are going to remove them to single volume element

there are diffrenet methods to clean up

some of them are planecut and some are normal cleanup

and normal clean up

after clean up with normal methods the grill looks like above ,and there should not be any triple cons

and elete every small faces avoid riple cons

B. faces offset option

Faces are offsetted and intersected and then deleted ,and topo clened up

To clean up bottom part of car to maintain symetry of model we use cons to curve option

and then cleanup the bottom part

Step 3:Cheaks manager

going to cheks manager we

55 errors are are single cons due to warning of single cons to join the other copy of car

Step 4: PId assignement

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

and also above given mesurements are for target length

Step 5:quality creiteria

from the given target lenghts we can approximate min length and max length and we ca set skewnes 0.5 and moveing to meshing ,

green colour cells are exeeded from quality criteria , we cant imrove manualy 416 cells , by clicking right clik over off elements and selecting reconstruct and agiain same process and then almost all off elements will be cleare in this process

if they are below 10 we can solve it manual my move option from grid section

here Frezzing is very important as to maintain quality of mesh

like wise we have to freez all pid's after imdieatly meshing them

Step 6: Creating copy of symetric by three points (mirror)

After creation mirror we can use paste optio for those cons with shareing same points

above image shows zero off elements

Step 7: Creating points for wind tunnel faces

X=length of Car

4X=From front of car

6x=From back off car

X=left and right of car

Step 8:

Meshing the wind tunnel and its faces meshlength grws from bottom to to 10mm to 100mm

by spaceing manual option

Result

fully meshed model with wind tunnel

Conclusion :From this we can conclude that from the quality criteria parameter make our mesh good mesh or stranded mesh