[mayank.dce2k7]

Hi Foamers,

I am trying to access flux at 'INLET' patch and set the B.C at 'OUTLET1' patch equal to 0.52 times the flux at inlet patch and B.C at 'OUTLET2' patch equal to 0.48 times the flux at inlet patch. Since I have specified parabolic velocity profile at inlet I don't know the exact value of flux at inlet so I need to access the flux at inlet somehow from within simulation. I am working to fix this bug for over a month but with no success.

I used below B.C's for setting flow rate B.C's at inlet and outlet:

INLET
{

type groovyBC;
variables "r2=(pow(pos().x,2)+pow(pos().z,2));R2=sum(are a())/pi;para=-((R2-r2)/R2)*normal();";
valueExpression "2*0.351*para"; //where 0.351 is the average velocity
value uniform (0 0 0);

}

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

OUTLET1
{

type flowRateInletVelocity;
flowRateExpression "0";
flowRate swak {
variables "phi1{INLET}=-0.52*sum(phi);";
expression "phi1"; // volume flow going out of domain from outlet 1 which 0.52 times that at inlet
valueType patch;
patchName OUTLET1;
};

value uniform ( 0 0 0 );
}

OUTLET2
{

type flowRateInletVelocity;
flowRateExpression "0";
flowRate swak {
variables "phi2{INLET}=-0.48*sum(phi);";
expression "phi2"; // volume flow going out of domain from outlet 1 which 0.52 times that at inlet
valueType patch;
patchName OUTLET2;
};

value uniform ( 0 0 0 );
}


Error message:

--> FOAM FATAL ERROR:
Continuity error cannot be removed by adjusting the outflow.
Please check the velocity boundary conditions and/or run potentialFoam to initialise the outflow.
Total flux : 0.000360325
Specified mass inflow : 0.000400984
Specified mass outflow : 0
Adjustable mass outflow : 0


From function adjustPhi(surfaceScalarField& phi, const volVectorField& U,const volScalarField& p
in file cfdTools/general/adjustPhi/adjustPhi.C at line 118.

FOAM exiting

The problem lies in using the expression "phi1{INLET}= -0.52*sum(phi)" here the value of "sum(phi)" is returned zero everytime and I am unable to understand why?