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boundary conditions for turbulence model

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Old   February 5, 2016, 05:34
Default boundary conditions for turbulence model
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Yage
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Dear All,

I would like to know the boundary conditions for k-omega model.

1. is there any scalable wall function in OpenFOAM?

My y+ values vary from 1 to 10.

According to the guidance http://www.dicat.unige.it/guerrero/o...turbulence.pdf

For 1<y+<300, use kqRWall and omegaWall function, and k wall value is set to be 0 and omega wall is set to be 10x6xnu/(0.075y^2)=51200 for my case.

The internalfield and other boundaries for k=3/2(UI)^2=0.04
and omega=(rho.k/mu).(mut/mu)^(-1)=400

Please help me check if these boundary conditions are reasonable.
And this is a problem: the k value at wall will change to 0.04 (internalfield value) after decompose to avoid crash. (OpenFOAM 2.3.0). and due to my experience, all other non-zero k wall value will also change to internalfield value, which confused me.

2. I further refined my mesh to y+=1~2 so that I dont need wall function, then which boundary condition should I use?

I tried fixedValue with 1e-10, but the simulation got a bounding k issue after several timestep and the pressure force on wall is extremely high. I used celllimited linear upwind for k and omega

So I have no idea how to solve this problem

Thanks in advance for your suggestion.

Regards,
Yage
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