reproducing k-omega model UDF/Wall function

alinik · May 2, 2017, 17:12

Hi all,

I am trying to reproduce the k-w turbulence model using UDF.
I have written all necessary parts and the result that I am getting is in the acceptable range.
The problem that I have right now, and I am not sure how to fix that, is the fact that I have to implement wall function for the cells adjacent to walls. I am not sure how to do that.
Do I have to manually specify velocity for cells in this region?
Does anyone here have any experience on how one can write a wall function in UDF?
Any kind of support is highly appreciatd.

Thanks,
Ali

alinik · June 16, 2017, 18:40

I am replying to my own post with the hope of receiving more attention.
Has anybody done the same thing ever before?

vcvedant · July 12, 2017, 15:27

If you want to write wall functions in UDF, first of all you must make sure that your y+ location is appropriate.
Then you can give the value of k, omega, U, V etc directly in the DEFINE_ADJUST() to their respective Scalars. You can use 'if' statements check the y+ values.

May 2, 2017, 17:12	reproducing k-omega model UDF/Wall function	#1
alinik Senior Member ali Join Date: Oct 2009 Posts: 318 Rep Power: 18	Hi all, I am trying to reproduce the k-w turbulence model using UDF. I have written all necessary parts and the result that I am getting is in the acceptable range. The problem that I have right now, and I am not sure how to fix that, is the fact that I have to implement wall function for the cells adjacent to walls. I am not sure how to do that. Do I have to manually specify velocity for cells in this region? Does anyone here have any experience on how one can write a wall function in UDF? Any kind of support is highly appreciatd. Thanks, Ali

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June 16, 2017, 18:40		#2
alinik Senior Member ali Join Date: Oct 2009 Posts: 318 Rep Power: 18	I am replying to my own post with the hope of receiving more attention. Has anybody done the same thing ever before?

July 12, 2017, 15:27		#3
vcvedant Member Vedamt Chittlangia Join Date: Feb 2016 Posts: 64 Rep Power: 9	If you want to write wall functions in UDF, first of all you must make sure that your y+ location is appropriate. Then you can give the value of k, omega, U, V etc directly in the DEFINE_ADJUST() to their respective Scalars. You can use 'if' statements check the y+ values.