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Dear all In my case of chan

Dear all

In my case of channelOodles, the result of velocity seems laminar profile(parabolic profile) even at turbulent condition.
I think something my setup is wrong, but I can't find it.

Values of my case model are below.

Re number=30000.

turbulenceProperties are
LESmodel: Smagorinsky
delta : vanDriest

Values of Ubar and nu are written on transportProperties file.

Y+ values are below 10.

initial value of k is zero.
inlet outlet conditions are cyclic.
Other conditions are refered from tutorial sample.

Best regards

 hjasak March 13, 2006 17:42

You should not start with initial k = 0. Estimate uPrime to several percent of uBar and do

k = 3/2 uPrime^2

as the initial guess of k.

Hrv

Thank you very much Hrv. I wi

Thank you very much Hrv.

 eugene March 14, 2006 09:32

What is your initial value of

What is your initial value of U?

The case will take ages to go turbulent from a uniform velocity unless you give it a push.

Hi Eugene Initial value of

Hi Eugene

Initial value of U is as same as value of Ubar for uniform, and I could get turbulent condition with my case. But the result of mean velocity profile is quite different from that of RANS result.

Is there any other value that I must check?

 eugene March 14, 2006 11:57

Hmm, above you said your U pro

Hmm, above you said your U profile was parabolic. The only way for that to happen is for the resolved flow to be laminar (at least in my experience).

Could you post a picture of the instantaneous U and k in the channel?

Please refer as below. U \

U
k

Sorry, I am not good at these

Sorry, I am not good at these kinds.

U
http://www.cfd-online.com/OpenFOAM_D...your_image.gif
k
http://www.cfd-online.com/OpenFOAM_D...your_image.gif

Dear Eugene Sorry, I couldn

Dear Eugene

But I thought that the problem is cyclic boundary condition will just loose kinetic energy every iterations.
Finaly, flow will become laminar.
How to give kinetic energy to flow every iterations?
Or is my understanding wrong?
Thanks.

 eugene March 25, 2006 10:00