Learning Forum

[Nikhil26]

Why we subtract car body from the enclosure during CFD simulation in Ansys?? What is the significance of boolean operation? And what if we preserve the tool body? Will it affect the results??

[peteroznewman]

CFD computes pressure and velocity in a fluid such as the air around a car body.  The car body is not a fluid, so there is no need to mesh the car body interior. However, the car body outside faces are present in the air domain after the car body is subtracted from a body of air enclosing that car body.

If you leave the car body in the geometry, you will have to mesh that, which is a waste of time, then you will have to assign that body a solid material, while the enclosure is assigned the material air.

[Nikhil26]

Thank u so much!!

And what if I suppressed the car body? 

Then I think there will be no need to mesh it! Am I right?

Can I go like this??

[Rob]

You can, but only after doing the split/subtraction. Otherwise you may find there is no car "hole" in the fluid domain. 

[dhanush M]

In boolean operation , I choose what domain for stationary and rotating parts (solid or fluid)

[NickFL]

Your rotating domain already has the blades removed, so you would leave this as "Fluid". In practice, we could always change this later and I never pay attention to it.