Week 4 Challenge : CFD Meshing for BMW car

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.

objective:

The given model should be cleaned up and different mesh parts should be meshed as per mentioned element size below. The entire model should be enclosed inside the enclosure and be considered as wind tunnel.

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:

At first import the model into ansa and check the model pid and all pid are successfully imported or not.

in first step we delete the one half of the model , we can make it as a complete car once we done cleanup on one of the model except the logo because it was not symmetrical. After we completion of all process we can mirror the model by using Transform option

Before creating surfaces we need to remove the triple cons,then we can create new surfaces on required area.

Now it's time to handle single cons.We use tools like projection, coons to curves,parametrical, multi project, Extend etc,. to eliminate the single and triple CONS. This process is done individually on each parts, for every part we ensure that the outer surface is retained as such. And for filling single cons with common end poits we use Paste tool to create a surface.

After the geometry surface clean up now mesh generation process will start

Mesh Generation:

MESHING OF INDIVIDUAL COMPONENTS ACCORDING TO THE GIVEN TARGET LENGTHS

Creating wind tunnel:

1. First, we need to create reference points to create wind tunnel surfaces.
2. Select relative under points in topo mode, create a point below the car taking one reference point and entering the correct values.
3. And calculating the wind tunnel dimensions appropriately, we can create the wind tunnel accurately.
4. The wind tunnel dimmensions are:

car model: 1306mm .................. (x)

Front surface distance(from reference points): 5875mm .................. (4x)

Back surface distance(from reference points): 8480mm .................. (6x)

Top surface distance(from reference points): 4323mm .................. (3x)

1. After creating the bottom surface use the curves for having the reference of cons, we can delete all the hot points and curves.
2. Create all the other wind tunnel surface using the new surface option.
3. 

Surafce meshing of wind tunnel:

1. We need to apply surface meshing depending the mesh length near the car and regions far away from it.
2. Therefore we need to apply different mesh lengths at the bottom and top wind tunnel surfaces.
3. We need to use spacing option to have a mesh length varying from the small mesh length size to larger mesh length.
4. Surface meshing can be achieved by doing this accordingly.

Results:

Learning Out comes :

Acquired knowledge of various new tools and how to use them to execute operations on given geometry. Construction of the Fluid domain was introduced newly.

Conclusions:

1) Finally BMW car model is topo-cleaned and surface meshed appropriately.

2) Wind tunnel is created and surface meshed with reference to the car model size.

Drive Link For File and Report file:

Click here to download The Model and My Report.