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BuouyantBoussineqLES pressure problem

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Old   May 29, 2013, 13:55
Default BuouyantBoussineqLES pressure problem
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Hello Foamies,

I'm trying to implement a turbulent flow field using the BuouyantBoussinesq solver.
My boundary conditions are at first as follows:

dimensions [0 1 -1 0 0 0 0];
internalField uniform (0 0 0);
boundaryField
{
left
{
type cyclic;
}
right
{
type cyclic;
}
top
{
type zeroGradient;
}
bottom
{
type fixedValue;
value uniform (0 0 0);
}
back
{
type cyclic;
}
front
{
type cyclic;
}
}


I'm using funkysetFields afterwards to write an initial wind- and pressure field.
Now the problem: After the first solver iteration the original pressure scales changes rapidly, even into negative scale. After a couple iterations this leads to singularities of unreal high numbers at the bottom corners of the flow domain. I attached two pictures for illustration purpose. The first shows the initial pressure field, second shows the build-up of the singularities.

Has anybody overcome similar problems with LES, or can give any advise on how to set the boundary conditions for the simulation of turbulent fields?

Thanks in advance,
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File Type: jpg pressure_time0.jpg (83.8 KB, 2 views)
File Type: jpg pressure_time10.jpg (90.4 KB, 3 views)
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Old   May 31, 2013, 04:55
Thumbs up Problem solved
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The pressure singularities were eleminated by using funkySetFields to set the right pressure levels to the flow domain. Afterwards I decreased the timesteps to 0.25 sec to keep Courant numbers low. After a couple of minutes timesteps were increased up to 1.0 sec. The pressure field was stable throughout the simulation run.
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