CFD Online Discussion Forums - [OpenFOAM] p is not a valid volScalarField

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- - [OpenFOAM] p is not a valid volScalarField (https://www.cfd-online.com/Forums/paraview/185918-p-not-valid-volscalarfield.html)

p is not a valid volScalarField

Hi,

I am running a simple case of the flow around a cylinder using the simpleFoam solver. I have created the mesh with snappyHexMesh and it looks fine when I open it in Paraview.

However, when I open the .foam file with paraview a error window pops up with one error message saying: "/Users/umberto/openfoam/cylinder/0/p is not a valid volScalarField".

If I ignore the message and run simpleFoam, I get a floating point exception after 14 iterations and the simulation stops.

I suppose the floating point error is linked to the volScalarField issue but I really can't figure out what's wrong with my p file:

Code:

/*--------------------------------*- C++ -*----------------------------------*\

| =========                 |                                                 |

| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |

|  \\    /   O peration     | Version:  plus                                  |

|   \\  /    A nd           | Web:      www.OpenFOAM.com                      |

|    \\/     M anipulation  |                                                 |

\*---------------------------------------------------------------------------*/

FoamFile

{

    version     2.0;

    format      ascii;

    class       volScalarField;

    object      p;

}

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //



dimensions      [0 -2 -2 0 0 0 0];



internalField   uniform 0;



boundaryField

{

    inlet

    {

        type            zeroGradient;

    }

    outlet

    {

        type            fixedValue;

        value           0;

    }

    cylinder

    {

        type            zeroGradient;

    }

    upperWall

    {

        type            slip;

    }

    lowerWall

    {

        type            slip;

    }

    frontAndBack

    {

        type            slip;

    }

}



// ************************************************************************* //

The p field is necessary in the 0 folder: It contains the initial condition. It seems that this file is not correct.

Your dimensions for pressure are as follows:

dimensions [0 -2 -2 0 0 0 0];

I think the dimensions of pressure for an incompressible case should be:

dimensions [0 2 -2 0 0 0 0];

Hope this helps,
Joshua

Well spotted. I am note sure why I had the wrong units there. However, changing the units did not solve my problem.

To me it looks like there is something substantial that is wrong with my p file but I really can't figure out what that is. It is also strange that I could not find anyone with the same issue.

Where else could the problem be?

If you calculate in 2D frontAndBack should be empty.

Nope that's not the issue. I am running 3D.

Just for the record, the issue was that I set the outlet value to 0 and not to uniform 0!

This is a bit late for a useful answer, but I want to add an observation (just for the record):

I had the same message with an p_rgh file. I used the fixedFluxPressure b.c.
If I changed that to fixedValue, the error disappeared. But the solution is not useful anymore :rolleyes: