CFD Online Discussion Forums - codedFixedValue to couple velocity and pressure?

I'm trying to simulate a Fan Filter Unit, when trying to model the HEPA filter at the output, I'm trying to impose the condition that for a small area, the outward velocity component builds up a pressure difference.
For example if the outflow velocity is 1m/s, the pressure on the inside surface of the filter is locally 10Pa; if the outflow is 2m/s, pressure inside is 20Pa.

This is different from the "type fanPressure" condition which sums the total flow rate, so I'm trying to use fixedCodedValue type condition.

the 0/p file contains this outlet patch:

Code:

out_hepaface

{

    type    codedFixedValue;

    value   $internalField;

    name    test;

    

    code

    #{

        scalarField& pField = *this;

        const vectorField& UFace = patch().lookupPatchField<volVectorField, vector>("U");

        const vectorField& np = patch().nf();



        int prop_coef = 1;

        forAll(pField, faceI) {

            pField[faceI] = prop_coef*UFace[faceI] & np[faceI];       

        }

    #};

}

The 0/U file contains :

Code:

out_hepaface

{

    type            pressureInletOutletVelocity;

    value           $internalField;

    inletValue      $internalField;

}

The solver is simpleFoam, and with deltaT = 0.001, it still makes sigFpe errors.

I've been learning OpenFOAM for only about 2 weeks so if you could kindly explain in detail if anything doesn't make sense.