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oliver September 2, 1998 09:12

two point averaging
What advantageous if any are gained for a turbulence model based on a 2 point averaging techniques.



Rasputin September 2, 1998 09:36

Re: two point averaging

Could you please elaborate on the concept of 2 point averaging and its relationship to turbulence modelling.

oliver September 2, 1998 11:23

Re: two point averaging
The correlation's for the majority of turbulence models are derived via one-point fluctuations. In order to derive the RANS equations the properties at one point in the flow can be expressed as the sum of the mean + fluc. Components. However two point averaging is based on two points in the flow (i.e. at X and X+deltaX).

Models such as Rotta, (Zeiermann et al) and Anderson used two point averaging to obtain there first order closure models. Just heard of these T modelsI and I am not really familiar with such models.

All I want to know is what advantages are gained from two-point closure models, if any and why aren't they more available in Commercial CFD packages.

Thanks in Advance


Stephane Baralon September 3, 1998 04:37

Re: two point averaging
Hi oliver,

I am not a specialist in the k-kl or k-t models, but from a physical point of view, a two-points correlation approach would be suitable for turbulence related process which are not local but, on the contrary , result from the contribution of several physical locations. A good example of that is the pressure-strain term that arises in the second-Order closure models.

Therefore, I would advise you to look at reviews of Speziale, one of the gurus in EARSM model.


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