[letoppina]

Hello,

I am trying to simulate a tube (solid region) in which a fluid is flowing inside (fluid region). I am using openFoam version 6 and the chtmultiregionfoam solver.



The fluid enters the tube at the inlet with a certain initial temperature, flows through the tube, reaches the outlet of the tube, and comes back in a sinusoidal fashion. So it means that once the fluid enters the tube, it remains inside and it moves back and forth. It interacts with the tube walls (which are heated) so the fluid will heat up and increase its temperature.


The fluid has a certain inlet temperature and inlet velocity but with time it should absorb the heat generated by the solid region. However, it seems that the at every repetition of the sinusoidal velocity cycle (at 0.1 Hz), the water inlet is always coming back to the initial input temperature. What I want is rather the evolution of the water temperature depending on the solid heat source, given an initial inlet temperature (occurring at t=0 only). How can I impose that?

I hope I am being clear.



This is the temperature for the water:

dimensions      [ 0 0 0 1 0 0 0 ];

internalField   uniform 293.15;

boundaryField
{
    #includeEtc "caseDicts/setConstraintTypes"

    minX
    {
        type            fixedValue;
        value           $internalField;
    }
    maxX
    {
        type            zeroGradient;
    }
    "(min|max)(Z)"
    {
        type            empty;
        ~value;
    }
    "water_to_.*"
    {
        type            compressible::turbulentTemperatureCoupledBaffleMixed;
        value           $internalField;
        Tnbr            T;
        kappaMethod     fluidThermo;
    }
}

And this is the code for the water velocity:

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

internalField   uniform (0 0 0);

boundaryField
{
    #includeEtc "caseDicts/setConstraintTypes"

    minX
    {    
        type        uniformFixedValue;
    uniformValue sine;
        uniformValueCoeffs
        {
            frequency 0.1;
            amplitude 0.015;
            scale     (0.7 0 0); 
            level     (0 0 0); 
            t0        0; 
        }          

    }
    maxX
    {
    type         pressureInletOutletVelocity;
    value           $internalField;
    }

    "(min|max)(Z)"
    {
        type            empty;
        ~value;
    }

    "water_to_.*"
    {
        type            noSlip;
    }
}

Thank you for your help!