[sudheer717]

Dear Foamers,

I am trying to simulate an axisymmetric thermal jet and for that I am using buoyantBoussinesqPimpleFoam solver. I am having trouble with the boundary conditions.

I kept the temperature difference between inlet flow and surroundings as 20K so as to satisfy the Boussinesq condition. What solver is suggested if I were to use a larger temperature difference.

The case is running fine for few time steps and suddenly I am getting 'nan' values. Timestep is adjustable and max Co number is set to '0.5'. ddt scheme is 'CrankNicolson 1.0'; and 'Gauss linear' for div schemes

In post-processing I saw that my velocity has reached the sides when 'nan' starts coming.

Ay help is highly appreciated.

My case set-up is as follows:

1) I have 4 parts, Inlet,Walls,Outlet-Patch type and Base is of wall type. Generated msh file using ICEM and has around 1 million cells.

2) I am using k-e model as of now

3) My inlet velocity is around 1m/s

and details from 0/ directory:

p_rgh file: 

internalField   uniform 0;

boundaryField
{
    INLET
    {
        type            fixedFluxPressure;
        rho             rhok;
        value          uniform 0;
    }
    OUTLET
    {
        type            zeroGradient;
    }
    WALLS
    {   
        //type            fixedFluxPressure;
        //rho              rhok;
        //value           uniform 0;
        type            totalPressure;
        p0              uniform 0;
        gamma           1.4;
        value           uniform 0;
    }
    BASE
    {
        type           fixedFluxPressure;
        rho             rhok;
        value          uniform 0;
    }
}

p file:

internalField   uniform 0;

boundaryField
{
    INLET
    {
        type            calculated;
        value           $internalField;
    }
    OUTLET
    {
        type            calculated;
        value           $internalField;
    }
    WALLS
    {
        type            calculated;
        value           $internalField;
    }
    BASE
    {
        type            calculated;
        value           $internalField;
    }
}


U file:

internalField   uniform (0 0 0);

boundaryField
{
    INLET
    {
        type            fixedValue;
        value           uniform (0 0.98 0);
    }
    OUTLET
    {
        type            inletOutlet;
        inletValue      uniform (0 0 0);
        value           uniform (0 0 0);
    }
    WALLS
    {
        //type            inletOutlet;
        //inletValue      uniform (0 0 0);
        type            pressureInletOutletVelocity;
        value           uniform (0 0 0);
    }
    BASE
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }

}

T file:

internalField   uniform 300;

boundaryField
{
    INLET
    {
        type            fixedValue;
        value           uniform 320;
    }
    OUTLET
    {
        type            inletOutlet;
        value           uniform 300;
        inletValue      uniform 0;
    }
    WALLS
    {
        type            inletOutlet;
        value           uniform 300;
        inletValue      uniform 0;
    }
    BASE
    {
        type            zeroGradient;
    }
}

Thank you
-Sudheer

[Rebeca]

Hi! I'm trying to solve a similar problem. Could you finally solve your boundary conditions' problem?