pressure profile

alicfd · February 25, 2011, 12:37

Hi everyone
I have a problem with following UDF. I want to apply pressure on BC that pressure harmonizes with gradient vector! But when I init it, I accept error!
#include "udf.h"
#define viscosity 0.0029

DEFINE_PROFILE(Pressure_Profile , t , i){
cell_t c ;
begin_c_loop(c , t ){

C_PROFILE(c , t , i ) =2*viscosity*C_U_G(c , t )[0] ;
}
end_c_loop(c , t)
}
I think its reason is that Fluent isn’t solved equations yet. My problem is steady state!!
How can I apply folllowing BC?
P=2*viscosity*(du/dx)
Thanks a lot.
Kid Ali.

Amir · February 25, 2011, 13:23

Hi Ali,
first, you should use compiled UDF not interpreted one.
second,to keep gradient values you should use this TUI command:
solve/set/expert
if they didn't help, you can define gradient yourself.

February 25, 2011, 12:37	pressure profile	#1
alicfd New Member kid ali Join Date: Feb 2011 Posts: 1 Rep Power: 0	Hi everyone I have a problem with following UDF. I want to apply pressure on BC that pressure harmonizes with gradient vector! But when I init it, I accept error! #include "udf.h" #define viscosity 0.0029 DEFINE_PROFILE(Pressure_Profile , t , i){ cell_t c ; begin_c_loop(c , t ){ C_PROFILE(c , t , i ) =2viscosityC_U_G(c , t )[0] ; } end_c_loop(c , t) } I think its reason is that Fluent isn’t solved equations yet. My problem is steady state!! How can I apply folllowing BC? P=2viscosity(du/dx) Thanks a lot. Kid Ali.

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February 25, 2011, 13:23		#2
Amir Senior Member Amir Join Date: May 2009 Location: Montreal, QC Posts: 735 Blog Entries: 1 Rep Power: 22	Hi Ali, first, you should use compiled UDF not interpreted one. second,to keep gradient values you should use this TUI command: solve/set/expert if they didn't help, you can define gradient yourself.