Smagorinsky-Lilly model

(Difference between revisions)
 Revision as of 21:46, 1 May 2006 (view source)Jasond (Talk | contribs)m← Older edit Revision as of 12:20, 8 May 2006 (view source)Salva (Talk | contribs) mNewer edit → Line 1: Line 1: The Smagorinsky model could be summerised as: The Smagorinsky model could be summerised as: :$:[itex] - \tau _{ij} - \frac{1}{3}\tau _{kk} \delta _{ij} = - 2\left( {C_s \bar \Delta } \right)^2 \left| {\bar S} \right|S_{ij} + \tau _{ij} - \frac{1}{3}\tau _{kk} \delta _{ij} = - 2\left( {C_s \Delta } \right)^2 \left| {\bar S} \right|S_{ij}$
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Line 8: Line 8: :$:[itex] - \mu _{sgs} = \rho \left( {C_s \bar \Delta } \right)^2 \left| {\bar S} \right| + \mu _{sgs} = \rho \left( {C_s \Delta } \right)^2 \left| {\bar S} \right|$ [/itex]

Line 14: Line 14: Where the filter width is usually taken to be Where the filter width is usually taken to be :$:[itex] - \bar \Delta = \left( \mbox{Volume} \right)^{\frac{1}{3}} + \Delta = \left( \mbox{Volume} \right)^{\frac{1}{3}}$ [/itex]

Revision as of 12:20, 8 May 2006

The Smagorinsky model could be summerised as:

$\tau _{ij} - \frac{1}{3}\tau _{kk} \delta _{ij} = - 2\left( {C_s \Delta } \right)^2 \left| {\bar S} \right|S_{ij}$

In the Smagorinsky-Lilly model, the eddy viscosity is modeled by

$\mu _{sgs} = \rho \left( {C_s \Delta } \right)^2 \left| {\bar S} \right|$

Where the filter width is usually taken to be

$\Delta = \left( \mbox{Volume} \right)^{\frac{1}{3}}$

and

$\bar S = \sqrt {2S_{ij} S_{ij} }$

The effective viscosity is calculated from

$\mu _{eff} = \mu _{mol} + \mu _{sgs}$

The Smagorinsky constant usually has the value:

$C_s = 0.1 - 0.2$