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-   -   where is the origin of a boundary face for udf (http://www.cfd-online.com/Forums/fluent/42021-where-origin-boundary-face-udf.html)

ma jie August 14, 2006 08:32

where is the origin of a boundary face for udf
 
Dera sir/madam:

I am a fluent user from China. And I have a very simple question to ask for you. When I was writing a udf file for a prssure inlet boundary to set the static pressure which is changing with z cordination,I don't know where the origin of the boundary face is ,so the results are always wrong. I would very appreciate if you have time to tell me the right answer.Thank you for your reply. Sincerely yours,

Ma jie

06.8.14 My udf file are as follows:

#include "udf.h" DEFINE_PROFILE(pressure_inlet_static,thread,index) { real x[ND_ND]; real z; face_t f; begin_f_loop(f,thread) {

F_CENTROID(x,f,thread);

z=x[2];

F_PROFILE(f,thread,index)=9800*(13.6-z); }

end_f_loop(f,thread) }


karolw August 14, 2006 15:21

Re: where is the origin of a boundary face for udf
 
You should not worry about the origin, the z coordinate is the absolute location regarding the origin of your mesh. The following line looks suspicious:

F_PROFILE(f,thread,index)=9800*(13.6-z);

Is your model actually this big? Remember that the length units are meters.


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