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UnderGroundMan November 7, 2008 14:48

what are reynolds stresses

When I run LES problem I get variables called reynolds stresses in post. Physically what are reynolds stresses? Thank you.

Hossam November 8, 2008 22:18

Re: what are reynolds stresses
a very brief definition of the reynolds stresses (also called the turbulent stresses)would be the shear and normal stresses due turbulent fluctuations. actually the fundamental problem of the turbulent flow since the days of Reynolds 1896 untill now is how to model those stresses in order to close the system of equations, however, when using LES you are resolving them directly not modelling them, at least you are resolving the stresses which are due to the turbulent eddies larger than the grid cells, and modelling those that are smaller than the grid cells. thus you should be careful when generating the grid.

underGroundMan November 10, 2008 13:31

Re: what are reynolds stresses
Hi Hossam

In CFX-Post which stresses are have been directly resolved and which ones have been modelled. I have only found statistical reynolds stresses. Are they for resolved flow or modelled flow. Thanks you

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