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Roued February 1, 2000 16:38

Reynolds Stress Models
 
Hi, every one

I have e general question about using the Reynolds Stress models (RSM and ASM) within CFX.

When simulating air flow in ventilated enclosures like a building or a room, the quality of the prediction made by the Reynolds Stress models are poor compared to the two-equations model like k-eps, low-Reynolds k-eps or the low-Reynolds k-omega models. (Comparing velocity profiles, between different turbulence model and experiments).

The flow is in general low-Reynolds (RE approx. 4000-5000). Room has slot inlet and outlet in full width of the room.

Why does the RSM make such a poor prediction ???

Any hints ???

Only standard parameter are used both in the Reynolds Stress Model and the other two-equations models.

Thanks in advance.

Best Regards

Roued

ahmadreza hosseinkhani February 2, 2000 10:45

Re: Reynolds Stress Models
 
hi dear friend probably, you must be use the near wall corrected R.S. model

thank you

a.r. hossenkhani Ph.D. student of hydraulic civil eng.

Gita February 7, 2000 11:33

Re: Reynolds Stress Models
 
Hi Roued,

Is your question about RSM within the context of CFX or in general? If it's general and you want to know why RSM is poor compared to other models, then I can share some of my knowledge with you. I have used CFX once and I don't remember it now(as I don't have the code). I had a course in turbulence and during that time I came to understand some of the aspects of turbulence. The very basic deficiency of RSM is the "closure". We don't have any clear physical understanding of the problem in concern in order to close the unknowns that RSM introduces thro' averaging. That's why it works well for some problems and fails in some others. gita


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