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jahed1775 July 8, 2012 15:28

Reynolds stress calculation in Starccmplus
Hey guys, can anyone help how to get reynolds shear stress in starccmplus from k-epsilon or v2f model. Will really appreciate.


flotus1 July 8, 2012 17:02

The components of the Reynolds stress tensor are not available with a k-epsilon model.
The turbulent kinetic energy k only represents the values on the diagonal of the reynolds stress tensor -> k=1/2*(uu+vv+ww)

The individual components are only accessible with a Reynolds-stress turbulence model, a LES or a DNS.

Far July 9, 2012 04:57

Can we find them through velocity gradients and eddy viscosity?

flotus1 July 9, 2012 07:48

Unfortunately, we can't.
That is one of the disadvantages of two-equation turbulence models.
We only have two equations for turbulence quantities. The Reynolds stress tensor contains 6 independent variables.

Unless we use a turbulence model with 6 additional equations (like a reynolds stress model) or we obtain the reynolds stresses explicitly wit a LES or DNS, we don't have enough information about the flow to give an estimate for the individual components of the Reynolds stresses.

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