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-   -   Variable mass flow at boundary (http://www.cfd-online.com/Forums/fluent/32563-variable-mass-flow-boundary.html)

Dimitrios November 20, 2003 09:01

Variable mass flow at boundary
 
Hi fellow Fluent users...

As I'm new to this software, everything feels and is strange.....my newest problem though is that I have a boundary with variable mass flow rate due to changes in area. Can I specify this variation in Fluent or do I have to do it in another way?

ap November 20, 2003 09:52

Re: Variable mass flow at boundary
 
You can implement it using UDF.

Hi :)

ap

Dimitrios November 20, 2003 10:03

Re: Variable mass flow at boundary
 
Thanks a bunch ap

mateus November 20, 2003 10:13

Re: Variable mass flow at boundary
 
Hi!

Your Udf shoul look something like this (it's an axample from udf fluent documentation - for variable velocity inlet)

/************************************************** ********************

unsteady.c

UDF for specifying a transient velocity profile boundary condition ************************************************** *********************/

#include "udf.h"

DEFINE_PROFILE(unsteady_velocity, thread, position) { face_t f; real t = CURRENT_TIME;

begin_f_loop(f, thread)

{

F_PROFILE(f, thread, position) = 20. + 5.0*sin(10.*t);

} end_f_loop(f, thread) }

regards

MATEUS

Dimitrios November 24, 2003 11:20

Re: Variable mass flow at boundary
 
Don't they have a similar thing for variable mass flux inlet among the udf examples?

co2 November 26, 2003 15:05

Re: Variable mass flow at boundary
 
I wish they had examples to serve all our research problems ! life would be so easy then !

Dimitrios November 27, 2003 03:24

Re: Variable mass flow at boundary
 
You don't say? LOL


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