Hello, I want to solve a simple channel flow by using Van-Driest Damping funtion by LES. Did anyone use Van-Driest in FLUENT? I supposed I had to write a UDF. I tried many times, but I could not acieved yet. Actually the problem is that, FLUENT gives some errors when I want to interpret the funtion. I can give the details about the errors and/or the UDF I have written before. Thank you very much...

Try writing your udf as a compiled function. Interpreted functions often fail except for the simplest udf's.