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-   -   LTSInterFOam (http://www.cfd-online.com/Forums/openfoam/115260-ltsinterfoam.html)

Tobi March 27, 2013 06:27

LTSInterFOam
 
Hi all,

I am working with interFoam over an year and try to use the LTS now.

For that I do not know what these options are and used for:

Code:

    nAlphaSweepIter 1;

    rDeltaTSmoothingCoeff 0.1;
    rDeltaTDampingCoeff 1;
    maxDeltaT      0.8

Can someone tell me how I can interprete that coefficients?

sail March 27, 2013 09:42

LTS uses a method that "assign at each cell a local time" so you can have a pseudo time advancement not constrined by the cfl condition in the smaller cell.

but you either don't want huge differences of time across neighboring cells, so the dampening coeff prevents oscillations in a checkboarding manner and the smoothing is to avoid spikes and have the local timestep as "smooth" as possible across nearby cells.

Tobi March 29, 2013 12:28

Quote:

Originally Posted by sail (Post 416721)
LTS uses a method that "assign at each cell a local time" so you can have a pseudo time advancement not constrined by the cfl condition in the smaller cell.

but you either don't want huge differences of time across neighboring cells, so the dampening coeff prevents oscillations in a checkboarding manner and the smoothing is to avoid spikes and have the local timestep as "smooth" as possible across nearby cells.

Hi,

thanks for your replay.

So the two coefficents helps to stabilize the numeric


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