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-   -   Modification of turb. viscosity using UDF? (https://www.cfd-online.com/Forums/fluent/32221-modification-turb-viscosity-using-udf.html)

 moon September 28, 2003 15:48

Modification of turb. viscosity using UDF?

If I use the standard k-e and the enhanced wall treatment for turbulence model, and define new turb. viscosity using UDF, What model will be changed?

is that standard k-e or wolfshtein's 1-eq. model in enhanced wall treatment?

thank you.

 Martin September 29, 2003 04:47

Re: Modification of turb. viscosity using UDF?

hi,

i had the same problem... with that udf you change the standard turbulent viscosity. on which problem you are working? perhaps we have the same...

 moon September 30, 2003 14:20

Re: Modification of turb. viscosity using UDF?

I used enhanced wall treatment for a pipe flow. but its prediction(skin friction, wall temp.) is so poor when reynolds number is small. so, I want to change the turb. viscosity as other equation. In this work, I have no idea, I'm sorry. now, I just want to know the possibility of that. If I get the idea from the forum, It will make me happy.

 Martin October 1, 2003 14:15

Re: Modification of turb. viscosity using UDF?

hi, sorry, i was wrong. you can change turbulent viscosity with udf. this new turbulent viskosity is computed for the whole domain (viscous affected region and fully turbulent). if you want different calculation in these two regions, you have to do on your own...

 moon October 2, 2003 11:19

Re: Modification of turb. viscosity using UDF?

In FLUENT, is new turbulent viscosity using UDF for the whole domain? I don't want different calculation in two regions. I just want to improve the prediction for a pipe flow. Can I get the information about the modification of turbulent viscosity for better result? for example, thesis, paper, book... except FLUENT manual.

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