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-   -   setup of inital condition (http://www.cfd-online.com/Forums/openfoam/79951-setup-inital-condition.html)

gija79 September 9, 2010 06:55

setup of inital condition
 
1 Attachment(s)
hi
I would like to simulate an unsteady flow with a linear thermal gradient (with the vertical depth Z) at inlet.
The all dominion should be initialized with the same gradient.
How can I impose these value of temperature to the internal mesh? the simplified problem is something like the image attached.
Suggestion about the solver to use?
Thanks Silvia

Edison_Ge September 10, 2010 12:14

You may need to do some modification on the source code for new inlet boundary. http://www.tfd.chalmers.se/~hani/kur...yCondition.pdf
This pdf may help you find a way.

Edison_Ge September 10, 2010 12:25

actually, it may be easier that. Take a look at the discussion http://www.cfd-online.com/Forums/ope...-openfoam.html
and then check the user guide 4.2.9. Hope it may help.

santiagomarquezd September 10, 2010 13:52

Did you try funkySetFields?

Bye.

gija79 September 23, 2010 12:30

bouyantboussinesqpimpleFoam
 
thanks for the suggestions. I used funkysetfields for temperature gradient and
timeVaryingUniformFixedValue for unsteady conditions at inlet.
The fluid to simlate to is water, so uncompressible
About the solver:
I tried to use bouyantboussinesqpimpleFoam putting the following boundary conditions:


U
internalField uniform (0 0 0);

boundaryField
{
inlet : timeVaryingUniformFixedValue;

outlet: zeroGradient;

bottom fixed value uniform (0 0 0);

atmosphere zeroGradient;

defaultFaces empty (2D case)
}

T

inlet
type fixedValue;
value nonuniform
All other boundaries are set as zerogradient.


p
inlet
{
type zeroGradient;

}
outlet
{
type fixedValue;
value uniform 0;

}
bottom
{
type zeroGradient;
}
atmosphere
{
type fixedValue;
value uniform 0;

defaultFaces
{
type empty;

For thermopysical aspect I use the folowing:

thermoType hPsiThermo<pureMixture<constTransport<specieThermo <hConstThermo<icoPolynomial>>>>>;

mixture water 1 18 4190 0 1.001e-03 10;

pRef 100000;



I tried with and without gravity but the temperature field seems to become crazy, with value too high!

Did I make some big mistake or should I consider a different solver?
and which one?
thank you
Silvia


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