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Ashraf September 29, 2004 15:27

determination of wall shear stress
 
This is Ashraf from USC, Columbia. I am trying to determine the wall shear stress of a domain using FLUENT. I am using the k - epsilon model to solve the problem, but the result is far away from what I expect. Can anyone give me any suggestion about what would be the best method to solve wall shear stress?

Titiksh Patel September 30, 2004 05:39

Re: determination of wall shear stress
 
Hi,

Use fine B.L. near the wall. keep u*~= 4 or 5.

But I am not sure how canu calculate u* prior to simulations..!!

Titiksh

svh September 30, 2004 07:20

Re: determination of wall shear stress
 
The most important point to gain a suitable response is to creat a correct mesh. Hope be successful.

svh

Ashraf September 30, 2004 10:56

Re: determination of wall shear stress
 
I checked the mesh, seems it has no problem. velocity profiles look ok to me also. actually wall shear stresses are calculated automatically, you don't need to calculate u*. but the values doesn't seem ok to me

Ashraf

Titiksh Patel September 30, 2004 13:22

Re: determination of wall shear stress
 
Hi

check y+ values...

I am lookinn into more details.

Regards, Titiksh

Ashraf September 30, 2004 14:29

Re: determination of wall shear stress
 
Actually I checked the y+ values. So far I know, it should be greater than 50 to avoid interference with the laminar sublayer. it is ok in my case. But still it is not giving me correct results, this is giving me really hard time. I don't know whether any sort of special treatment is needed at the time of modelling


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