CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   OpenFOAM (http://www.cfd-online.com/Forums/openfoam/)
-   -   Boundary conditions for potentialFoam (http://www.cfd-online.com/Forums/openfoam/88060-boundary-conditions-potentialfoam.html)

 doubtsincfd May 7, 2011 02:59

Boundary conditions for potentialFoam

How can I specify boundary conditions for potentialFoam in terms of velocity potential? Or how can a dirichlet boundary condition for velocity potential be implemented in potentialfoam?

 nimasam May 8, 2011 04:05

is in the dirichlet boundary condition the value of velocity fixed or zero at boundary conditions? so use

{
type fixedValue;

value uniform (0 , 0 , 0);
}

 doubtsincfd May 8, 2011 04:33

I want to specify phi=constant boundary condition. Is there any way to specify boundary condition for phi? As per my understanding, it writes the phi values after convergence. We can only input U and P values.

 nimasam May 8, 2011 09:44

as i know phi = U & mesh.Sf() so when U is fixed at the boundary phi should be fixed too

 doubtsincfd May 8, 2011 14:26

Thank you. What does "U & mesh.Sf()" exactly mean mathematically? I am not aware of the syntax used in source code of openfoam. d(phi)/dn = Un, so does U & mesh.Sf() integrate U to get phi?

Also How do I then calculate U so that I get desired value of phi ? Do I have to go for trial and error?

 nimasam May 8, 2011 15:13

phi = U & mesh.Sf()
U= velocity vector
& = inner product
mesh.Sf() = normal surface vector

i guess you just need to divide ur desired phi into ur boundary area cross section,so you have desired U
then evaluate U in dict!

 doubtsincfd May 16, 2011 22:14

Basic confusion:

is phi flux or velocity potential?

 nimasam May 17, 2011 04:11

its flux :)

 All times are GMT -4. The time now is 22:23.