[Jonathan]

Hi guys,

i was just wondering whether anyone could shed some light on the following: i have been studying up on the formulation of the general RANS turbulence models, and have noticed that in the standard k-epsilon, the production term for k has:



where

is the mean strain tensor ...

In most of the intro CFD texts, it is pointed out that, for incompressible flow, div U = 0 and so, when calculating the Reynolds stresses, an additional term is incorporated to ensure the turbulence effects resulting from the normal Reynolds stresses are accounted for.

However, when you look at the production term in k-omega, there is an additional term included:



Could anybody explain why the additional term, which seems to be related to the normal Reynolds stresses is present in k-omega explicitly, when I would have thought this was already implied / incorporated in the strain tensor as in k-epsilon???

many thanks in advance!
regards
jonathan