[Pj.]

Hi everybody,

I'm looking for a way to impose the total pressure as inlet boundary condition, instead than a velocity.

My first try was to set the inlet with a fixedValue in both pressure and velocity, but this way the simulation gives bad results: even if i'm working with an incompressible flow, the flow rate decrease during the simulation. This should be obviously impossible in incompressible flow, but it happens.

After some research I found a pressure boundary condition called, indeed, totalPressure.
http://www.openfoam.org/docs/cpp/

    myPatch
 {
 type            totalPressure;
 U               U;
 phi             phi;
 rho             none;
 psi             none;
 gamma           1.4;
 p0              uniform 1e5;
 }

The problem is that I don't know what to write in the 0/U myPatch subDict. Should i set a fixedValue? Shouldn't it be free to vary (increasing when p decrease and vice versa) ?

What kind of BC do I have to set in the U file?
Do you have other advices about this topic?

Thank you very much,
Luca

[Thangam]

for a start you may want to look at pressureInletOutletVelocity b.c for your velocity at the outlet...I guess this is self adapting based on the pressure...I guess some more details on the case could be more helpful...