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How can I impose variable boundary conditions?

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Old   December 18, 2009, 16:53
Default How can I impose variable boundary conditions?
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Behrang Asgharian
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Hi Guys!
How can I define variable boundary conditions such as variable temperature on a wall? I believe that I should use UDF. Which parts of the UDF Manual help me most. Any hint?
Thanks
Good luck
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Old   December 18, 2009, 20:43
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matth
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That's right you have ti write an UDF :
I used to do it with the velocity but it should be the same with the temperature. This is an example of a UDF of an unsteady velocity (you can find it in the UDF user guide of Fluent) (in the part boundary counditions and details UDF examples)


/************************************************** ********************
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)
}


When your UDF is written you have just to interpret it in Fluent !!!
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Old   December 20, 2009, 21:26
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Behrang Asgharian
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Thanks man.
I have started reading UDF Manual
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