CFD Online Discussion Forums - Implementation of a time varying heat sink

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Implementation of a time varying heat sink

I have implemented a constant heat sink for the chtMultiRegionSimpleFoam solver. I did it nearly the same way like they did it in this thread:

http://www.cfd-online.com/Forums/ope...rce-solid.html

Now I want to vary this heat sink over the time. I want to configure the heat sink in a table, the same way you do it with the uniformFixedValue boundary condition:

Code:

patch1

    {

        type            uniformFixedValue;

        uniformValue    table

        (

            (   0    300)

            ( 100    500)

            ( 200    300)

        );

    }

So I will have some values for some points in time. For other points in time the values will be computed by interpolation.

How can I implement this?

Quote:

Originally Posted by Koga (Post 392210)

Code:

patch1

    {

        type            uniformFixedValue;

        uniformValue    table

        (

            (   0    300)

            ( 100    500)

            ( 200    300)

        );

    }

So I will have some values for some points in time. For other points in time the values will be computed by interpolation.

How can I implement this?

Some of the solvers in 2.1 have something called "basicSource" built in (see for instance pimpleFoam) that allows you to do similar things (but you'll have to figure out how to use it, I've never used it in that form).

For some time swak4Foam has something called expressionSource that allows you to specify sources as expressions (how to add that to your solver search the message board for expressionSource)

The latest release of swak4Foam has a subclass of basicSource. So every solver that has basicSource built in can use a swakish source term (you'll have to load the library with libs in controlDict of cource).

And then there is always the possibility to hand-code it yourself ...

Thank you!

I found a solution for my purpose. I implemented a time varying heat sink which has a constant volumetric heat flux on the whole field.

I defined a config file where you can specify pointwise time and heat flux. Then I use linear interpolation to get the right heat flux value.

Hey Koga,

I've got a similar problem. I want to set up a surface heat flux which linearly decreases by time. Could you please post the settings for your sink in your 'T'-file? I tried "compressible::turbulentheatFluxTemperature" but unfortunately it won't accept a table as heat flux input.

I'd really appreciate your help.

Best regards

Robert

Hi Koga,

Can you place the code here with which you have modeled unsteady or time dependent heat sink.

I would appreciate it.

Best Regards,
Rohith