CFD Online Discussion Forums

CFD Online Discussion Forums (
-   FLUENT (
-   -   porosity in UDF (

Jin Yan February 22, 2004 12:40

porosity in UDF
Hello, I have a question about prosity. Can I modify the porosity to be dependent on pressure in UDF? How to use the porosity in UDF? I can't find this variable in UDF guide.

Thank you!


Andrew Garrard February 22, 2004 13:02

Re: porosity in UDF
I had a quick look at the documentation myself, but I couldn't find a way of setting the porosity either. However, when I come to simulate a porous zone I tend to write my own UDF's rather than the fluent built in ones. The fluent porous models are simply momentum sinks in the source terms for x y and z momentum. If you write your own porous model you can set porosity to whatever you want.

Just a thought.

ccc February 23, 2004 06:05

Re: porosity in UDF
hi jinyan,

add the following macro into your udf and you can use it just as C_U, C_P, and etc.

#define C_POR(c,t) C_STORAGE_R(c,t,SV_PRO)

However, I am not sure of its validation. You should do some tests by youself.

good luck.

Craig February 23, 2004 18:51

Re: porosity in UDF
You can alter porosity with a DEFINE_PROFILE UDF. (the Fluent manual tells you to use DEFINE_PROPERTY which doesn't work). In your UDF, make it a function of pressure.

WSWGg December 1, 2009 10:27

Use C_PROFILE function DEFINE_PROFILE UDF, it works - I tested.

All times are GMT -4. The time now is 21:58.