Unrealistic supersonic pockets at pressure inlet
 

Hi!

For my undergrad project I am trying to simulate an airfoil in a wind tunnel using the sonicFoam solver. I run the case on a big domain with fixed velocity inlet and worked fine. When moved to pressure inlet I am struggling. As you can see from the picture with the bent duct, there are pockets of insanely high speeds (up to Mach 9). The boundary conditions are fixed value (1.6 bar and 1 bar wave trasmissive) at both the inlet and outlet and the velocity BC are fixedGradient. I am trying to achieve inlet velocity of Ma 0.4 and this should be done by having constant pressure inlet. I have been trying everything and pretty desperate right now.
When testing the pressure conditions with the big domain, i dont get the pockets but the strange flow pattern near the outlet.

What am I getting wrong?!

U
dimensions [ 0 1 -1 0 0 0 0 ];
internalField uniform (0 0 0);
boundaryField
{
back
{
type zeroGradient;
}

front
{
type zeroGradient;
}

top
{
type fixedValue;
value uniform ( 0 0 0);
}

right
{
type zeroGradient;
}

bottom
{
type fixedValue;
value uniform ( 0 0 0);
}

left
{
type pressureInletVelocity;
value uniform (0 0 0);
}
foil
{
type fixedValue;
value uniform ( 0 0 0);
}

}

P
dimensions [ 1 -1 -2 0 0 0 0 ];
internalField uniform 100000.0;
boundaryField
{
back
{
type zeroGradient;
}

front
{
type zeroGradient;
}

top
{
type zeroGradient;
}

right
{
type waveTransmissive;
field p;
phi phi;
rho rho;
psi thermo:psi;
gamma 1.3;
fieldInf 100000;
lInf 1;
value uniform 100000;;
}

bottom
{
type zeroGradient;
}

left
{

type fixedValue;
value uniform 160000.0;
}

foil
{
type zeroGradient;
}

}





Thank you so much