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Strain rate calculation for explicitly filtered constant smagorinsky model |
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December 1, 2013, 09:25 |
Strain rate calculation for explicitly filtered constant smagorinsky model
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#1 |
New Member
MMS
Join Date: Nov 2013
Posts: 29
Rep Power: 13 |
I have very vague idea about this, if some one help me to understand it will be great help.
In the constant Smagorinsky model, during the calculation of turbulent viscosity (Nu_t) we need the magnitude of the strain rate. For the implicitly filtered LES, Nu_t will be Nu_t = (Cs*DELTA)**2*STRAIN_RATE Where, Cs=0.2, DELTA= (dx*dy*dz)^(1/3)= almost equal to the cell size (h). and the magnitude of the strain rate measured for each cell in cell centre (if I am not wrong). But for explicit filtering, the filter width DELTA will be arbitrary value or multiples of cell size (h), let say DELTA=2*h. In that case how the strain rate will be linked with the filter size? Thanks. |
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December 1, 2013, 09:55 |
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#2 | |
Senior Member
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 6,897
Rep Power: 73 |
Quote:
The real measure of the filter widht is somehow uncertain both in implicit and explicit filtering... it is not true that is always delta=2h for explicit filtering, it depends on the effective way you adopt for performing filtering....you can find in literature some papers discussing about that |
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