Week 4 Challenge : CFD Meshing for BMW car

Aim:

Check and solve all geometrical errors and assign appropriate PIDs. Perform meshing with the given Target length.

Objective:

To practice on checking geometrical error, doing PIDs, learn about surface mesh, how to perform symmetry and how to make wind tunnel.

Body of content

Step 1

Insert Model

File<Open

Step 2

Mesh < Length < Perimeter as 1

Mesh < Length < Macros as 1

This help as to bring perfect size and shape of each and every component of car.

Step 3

Delete < Select half portion of car < Deselect logo < Middle click to confirm

Step 4

Removing tripple and single cons from the car

1. Light

Remove the internal component and deleting overlaped surface.

2. Front grill

Recontructing the grill < deleting unwanted parts < removing single and tripple cons

we apply same process of

removing tripple cons < single cons < recontructing surface < removing overlapped surface < deleting internal parts

3. Logo

4. Wind shield

5. Side glass

6. Rear glass and tail light

7.Fender and rear view mirror

8. Tyre (Front and rear)

9. Tail light and rear side.

10. For base surface

Curves < Cons to curve < Middle Click

Curves < Create curves < Select multlple points < Middle click

Delete the overlapped sufaces and reconstruct again with the help of curves and markings

Curves < Delete < Select all the surface < Middle click

Step 5

Applying PIDs

Properties < PID name (right click) < Select the object < Middle click

Apply to all the parts

Step 6

Meshing of Geometry

Classic mesh < Length < Perimeter < Select Object < Middle click < Enter value

Classic mesh < Length < Macros < Select Object < Middle click < Enter value

Mesh parameters < Select target length and element type < Click OK to confirm

Quality criteria < Select minimum and maximum length < Click OK to confirm

then

Classic mesh < Mesh Generation < Spot Mesh < Select object < Middle click to confirm

Given conditions

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

Shell mesh < Reconstruct < (Topo clean up) or (Grids < Move)

Step 7

Symmetry on other side

Hide logo < Transform < Copy < Entities < Select all parts < Middle click < Symmetry option < Select mirror 3 point plane < Select 3 points in car < Middle click < PID as No offset And Part as Same part < Finish(to confirm)

Geometry check

Checks<Geometry<Select all the required value<Execute

No error found

Step 8

Wind tunnel

Wind tunnel distance

From front face = Car distance from center to front + 4 X 1300 = 5854

From rear face = Car distance from center to rear + 6 X 1300 = 8410

Top face = Car height + 3 X 1300 = 4275

Bottom surface = -75 in Y direction

Side surface = 1300

1300 = Car length

Create curve and join points to create new surfaces

then assign PIDs and name

Classic mesh < Length < Perimeter < Select Object < Middle click < Enter value

Classic mesh < Length < Macros < Select Object < Middle click < Enter value

Mesh parameters < Select target length and element type < Click OK to confirm

Quality criteria < Select minimum and maximum length < Click OK to confirm

then

Classic mesh < Mesh Generation < Spot Mesh < Select object < Middle click to confirm

Top Surface target mesh length 100

Bottom surface target mesh length 20

For remaining four surfaces

Spacing < Biasing-Linear < Start factor-20 < End Factor-100 < Select four edges as shown in figure < middle click to confirm

Classic mesh < Mesh Generation < Spot Mesh < Select object < Middle click to confirm