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-   -   How to create an inlet with pressure gradient? (https://www.cfd-online.com/Forums/fluent/77905-how-create-inlet-pressure-gradient.html)

val17lr July 7, 2010 08:49

How to create an inlet with pressure gradient?
 
Hello!

I would like to create an inlet pressure gradient (with FLUENT) in order to study the behaviour of a pressure probe. This is a work i'm doing for my diploma thesis.

Unfortunatly, I don't know how to create this pressure gradient.

Could somebody help me please?

Regards

Valentin

val17lr July 7, 2010 09:00

Just a precision:

When I say "pressure gradient", I mean I want my pression to be greater on a side of the inlet (a square shape inlet) than on the opposite side (with a linear relation for example).

Sorry if what I wrote is not clear, but I'm french and it's a long time I I haven't learn English....

val17lr July 9, 2010 08:44

Please, I really need to know how to do that, I have alomost finish my dilploma thesis, but I miss this!!

fabolous July 9, 2010 09:05

got a similar problem with a temperature profile on a tube.
i think you have to use User defined functions.
here my example:
#include "udf.h"

DEFINE_PROFILE(temperature_profile,t,i)
{
real x[ND_ND];
real z;
face_t f;

begin_f_loop(f,t)
{
F_CENTROID(x,f,t);
z = x[2];
F_PROFILE(f,t,i) = 343.15 - 20.0*z/1.0;
}
end_f_loop(f,t)

}

here i wanna a temp at the begin of 343.15K(z=0m) and at the end 323.15K(z=1m)

to watch some more examples download the manual for UDF (Fluent)

good luck

val17lr July 12, 2010 05:49

Great!!

Thank you very much, I found it in the UDF manual.

However, I need to give an incidence angle to my pressure gradient (in the two direction x and z, it's a 3d problem), but I haven't find anything about this.

An Idea?

Regards

fabolous July 13, 2010 15:15

i recommend to write the function as you think it could be, and write a new thread.
i did the same, people answer you mostly if your question is concrete.

good luck


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