[Butcher]

Hi, I am trying the natural convection problem, hot water is in a steel cup kept on a surface. I have modeled the water, steel cup, surround air, and the surface(Marbel). The simulation keeps on hitting negative temperature for water.

I am adding the water boundary condition here. Please help.

 T
dimensions      [0 0 0 1 0 0 0];

internalField   uniform 356.75;

boundaryField 
{
    


    water_to_Glass
     {

        type            compressible::turbulentTemperatureRadCoupledMixed;
        value           $internalField;
        Tnbr            T;
        kappaMethod     fluidThermo;
    }

   water_to_Air
     {

        type            compressible::turbulentTemperatureRadCoupledMixed;
        value           $internalField;
        Tnbr            T;
        kappaMethod     fluidThermo;
    }
}

v
dimensions      [0 1 -1 0 0 0 0];

internalField   uniform (0 0 0);

boundaryField
{
    
    water_to_Glass
    {
        type            noSlip;
    }

    water_to_Air
    {
        type            noSlip;
    }

   
}

pgh
dimensions      [1 -1 -2 0 0 0 0];

internalField   uniform 1e5;

boundaryField
{
    water_to_Glass
    {
        type            fixedFluxPressure;
        value           uniform 1e5;
    }

    water_to_Air
    {
        type            fixedFluxPressure;
        value           uniform 1e5;
    }

    
}