CFD Online Discussion Forums (https://www.cfd-online.com/Forums/)
-   FLUENT (https://www.cfd-online.com/Forums/fluent/)
-   -   Effective thermal conductivity UDF - C_K_EFF?? (https://www.cfd-online.com/Forums/fluent/33002-effective-thermal-conductivity-udf-c_k_eff.html)

 Craig February 9, 2004 19:43

Effective thermal conductivity UDF - C_K_EFF??

Hi, I am modeling heat transfer in a porous media and get a parse error when I work with the macro C_K_EFF. I get a parse error in that line. If I replace with any other arbitrary macro, say C_K_L or C_MU_EFF or whatever I want it compiles fine. Using V6.1.

Anybody have any ideas why this doesn't work? My UDF is below.

#include "udf.h"

k_s=1.613*(4.62+.0001425*rho/mu*sqrt(u*u+v*v))*k_gas;

return k_s; }

 Rob Hart February 10, 2004 05:14

Re: Effective thermal conductivity UDF - C_K_EFF??

works fine in 6.0.20 here.

If you are feeling adventurous, you could have a browse through udf.h and see how C_K_EFF is defined.

In my #define udf.h C_K_EFF is:

#define C_K_EFF(c,t)(C_K_L(c,t) + C_K_T(c,t))

Rob

 Craig February 10, 2004 19:20

Re: Effective thermal conductivity UDF - C_K_EFF??

Thanks, actually C_K_T doesn't work either, probably because I'm not even using a turbulence model (I was confused - I didn't want K_EFF, I thought that referred to the effective conductivity of a porous medium).
However I do have another problem, I'm sure this must be something really simple I'm missing, I can't seem to load in more than 2 UDFs at once. If I try to interpret a second UDF, the first one is eliminated from the model. What do I need to do?
Thanks, much appreciated

 Rob Hart February 10, 2004 19:54

Re: Effective thermal conductivity UDF - C_K_EFF??

Well the obvious thing to do is put them all in one file.

To be honest I've never tried to have more than one .c file in a case.

Rob

 Craig February 11, 2004 15:02

Thank you Rob

Ahh, that was the simple thing that I was missing. Seems obvious to me now. Thanks for your help.

 All times are GMT -4. The time now is 12:02.