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Old   April 3, 2006, 13:19
Default pressure coefficient
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Dear friends,

After solution was converged and y+ < 400, the pressure coefficent was still larger than what I expected when just setting the free stream velocity at the inlet boundary as reference velocity. Now the result is 1.26, but in thetheory, it should be 0.7~0.9.

Could you tell me what the problem is?

Thanks in advance, Justin
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Old   April 4, 2006, 13:30
Default Re: pressure coefficient
CFD Guru
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What is tubulence model? What is the kind of near wall treatment you are using? What is the geometry? Is there flow separation taking place? If yes, then limit the y+ and bing it below 150 or so.

Use enhanced wall function approach and then report the results again.
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Old   April 5, 2006, 06:43
Default Re: pressure coefficient
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Thanks. Now I am studying wind environemnt around buildings. The used turbulence model and wall function are rng k-eps and standard funaction. the domain and model are boxes. The separation really occured. The problem is that if I set the lower y+ max allowed, the size of cas and dat files will increase from 150Mb to 800Mb and it will affect the speed of calculation. Can I just make the y+ of near the model wall lower than 150 and keep the other wall about 400?

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