[Edgar Alejandro Martínez]

Greetings,

I have a 2.5D case of a fluid past a square cylinder with heat transfer (images attached below). The mesh is done with blockMeshDict.

There's an inlet, outlet, the sides are declared as walls and the top and bottom are declared as symmetry planes (there are top_fluid and top_solid, same goes for bottom_fluid and bottom_solid).

The solid is kept at 500K (supposedly), the inlet velocity is water at 1m/s.

I used topoSetDict to create the regions and indeed you can visualize them in paraView, then I used splitMeshRegions -cellZones -overwrite to create the fluid-solid interfaces and they are created as well (although I can't see the patches in paraView).

The PROBLEM is that the solid region drops its temperature dramatically soon after the simulation begins (it reaches 300K which is the fluid's temperature). The fluid barely absorbs some heat and its temperature does not change dramatically (289K-302K).

I've tried small time steps but nothing works, the square cylinder is 10 X 10 cm and I really doubt it can be cooled to ambient temperature rapidly despite the fluid being water.

I've also tried modifying the scalarSemiImplicitSource (supposedly it has no time duration and I think it's supposed to heat permanently) but results don't change.

Here's the 0/fluid file for temperature:

 
dimensions      [ 0 0 0 1 0 0 0 ];

internalField   uniform 300;

boundaryField
{
    #includeEtc "caseDicts/setConstraintTypes"

    inlet
    {
        type            fixedValue;
        value           $internalField;
    }

    outlet
    {
        type            inletOutlet;
        value           $internalField;
        inletValue      $internalField;
    }

    "(left|right)"
    {
        type            zeroGradient;
    }

    fluid_to_solid
    {
        type            compressible::turbulentTemperatureCoupledBaffleMixed;
        value           $internalField;
        Tnbr            T;
        kappaMethod     fluidThermo;
    }

	"(top_fluid|bottom_fluid)"
	{
		type			symmetryPlane;
	}
}

Here's the 0/solid file for T:

dimensions      [ 0 0 0 1 0 0 0 ];

internalField   uniform 500;

boundaryField
{
    #includeEtc "caseDicts/setConstraintTypes"

    solid_to_fluid
    {
        type            compressible::turbulentTemperatureCoupledBaffleMixed;
        value           $internalField;
        Tnbr            T;
        kappaMethod     solidThermo;
    }

	"(top_solid|bottom_solid)"
	{
		type			symmetryPlane;
	}
}

Here's the fvOptions file:

options
{
	mySource
	{
        type    scalarSemiImplicitSource;
        active  true;

        scalarSemiImplicitSourceCoeffs
        {
        	selectionMode   all;
            cellSet      	c0;
            volumeMode      absolute;
            injectionRateSuSp
            {
            	T	(500 0);
            }
        }

	}
}

Thank you for your help and time.