[naveen k s]

Dear Foamers,
I'm working on the Flow over a car. I have doubts in the usage of boundary types (Geometric constraints) and Boundary condition's.

The following are the boundary types and boundary conditions i am using;


Inlet of the domain
Boundary type : patch
Boundary condition: Fixed value (certain value for velocity and zero gradient for pressure)


Outlet of the domain:
Boundary type: Patch
Boundary condition: inletOutlet (for velocity) and uniform zero (for pressure)


Car and ground:
Boundary type: Wall

Boundar condition:No slip condition (for velocity) and zero gradient for pressure


Top and Lateral sides:
Boundary condition: slip


What should be the boundary type that has to be used for the slip boundary condition?.
Does slip boundary condition along with boundary type as patch ensures infinite computational domain?
Suppose if Wall type boundary is used with slip boundary condition, whether the wall functions will still be applicable?


Waiting for your answers.

[metalfox]

The slip boundary condition is basically the same as a symmetry boundary condition (slipFvPatchField inherits from basicSymmetryFvPatchField). That means that for scalars is the same as zeroGradient, while for vectors it is zero gradient for the tangential component and zero value for the normal component.

What should be the boundary type that has to be used for the slip boundary condition?

I seem to remember that is patch. You can double check in the many tutorials that use this BC.

Does slip boundary condition along with boundary type as patch ensures infinite computational domain?

Not at all. It doesn’t ensure anything. Nevertheless, if your domain is large enough, this BC makes sense for these infinite boundaries. It also makes sense for front and back patches in 2D simulations.

Suppose if Wall type boundary is used with slip boundary condition, whether the wall functions will still be applicable?

This BC doesn’t make sense for walls.