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-   -   Y+ Values for Enhanced Wall Treatment (http://www.cfd-online.com/Forums/fluent/38648-y-values-enhanced-wall-treatment.html)

Gerd November 17, 2005 06:49

Y+ Values for Enhanced Wall Treatment
 
Hello, I want to ask how strict the range 1< Y+ <5 for Enhanced Wall treatment is, and what Fluent is computing if the Y+ Values differ from this range. Is a Y+ Value of 0,9 still ok. What about 0,25 or 0,5? Kind Regards Gerd Sattler

Alan November 17, 2005 07:38

Re: Y+ Values for Enhanced Wall Treatment
 
Hi Gerd,

Put simply, it depends on your application!

Alan

Rajesh November 17, 2005 21:49

Re: Y+ Values for Enhanced Wall Treatment
 
This question has been addressed by pUl| long back. Read this (4th comment)

http://university.fluent.com/blog/in...&pb=1#comments

Rajesh

Gerd November 20, 2005 16:00

Re: Y+ Values for Enhanced Wall Treatment
 
Hello Rajesh, thanks for ur response. The comment u showed me is concerned with the Y+ Values for standard wall funktions, but I am working with enhanced wall treatment. So I am not sure in how far it can help me in solving my problem. I heard that fluent uses wall funktions if the Y+ value is too high, but what happens if it is too low for enhanced wall treatment? In my simulation the Y+ value is at the channel wall about 0,92 and at a bluff body just a few cells have a value of about 0,5. I guessed it is ok, cause the cells with those low Y+ values are near the walls and shouldned habe too much influence on the results of my simulation. Kind Regards Gerd

Rajesh November 20, 2005 20:28

Re: Y+ Values for Enhanced Wall Treatment
 
It is suggeted in the Fluent manual that, for the enhanced wall traetment one can use a Y plus value of ~1. So as you told, if you have y plus values of 0.92 and 0.5, I think it won't make problems in your results, provided you feel fine with the no. of meshes! (depending on the Reynolds number)

Rajesh

Gerd November 21, 2005 09:23

Re: Y+ Values for Enhanced Wall Treatment
 
Thanks for ur help. I also guessed it should be ok. But its nice to see me confirmed. Kind Regards Gerd


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