CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   FLUENT (http://www.cfd-online.com/Forums/fluent/)
-   -   Sunction Boundary Condition (http://www.cfd-online.com/Forums/fluent/98596-sunction-boundary-condition.html)

Akim679 March 14, 2012 12:37

Suction Boundary Condition
 
Hi,

I am trying to solve a problem in which the channel is rectangular and the bottom wall will have a suction, meaning the fluid near the bottom wall will go downward with a certain velocity. How would I specify such boundary condition in FLUENT?

Thanks,
Akim

ghost82 March 15, 2012 10:40

Pressure outlet?
I'm not sure if you can set a mass flow inlet or a velocity inlet and then if you can specify a negative value...

I'm not sure I understand your proble..post a picture.

Daniele

Akim679 March 15, 2012 15:31

Porous wall
 
Actually,

My adviser told me to model a wall as a "porous wall" which will allow fluid to seep through. Is there a way to specify that in FLUENT?

Thanks,
Akim

cdf_user March 16, 2012 01:04

put ur suction boundary as pressure outlet
write a udf using DEFINE_PROFILE and place it on this boundary..should work

I am doing the same thing except my boundary is oscillating suction and injection.

Akim679 March 16, 2012 12:30

Would you kindly elaborate on writing the UDF on the "DEFINE_PROFILE". I'm not too sure on UDFs.

Thanks,
Akim

cdf_user March 16, 2012 13:07

/************************************************** ********************/
/* unsteady.c */
/* UDF for specifying a transient velocity profile boundary condition */
/************************************************** ********************/

#include "udf.h"

DEFINE_PROFILE(SJ_velocity, thread, position)
{
face_t f;

begin_f_loop(f, thread)
{
real freq=25.;
real vol=400.;
real spd=vol/520.;
real t = RP_Get_Real("flow-time");
F_PROFILE(f, thread, position) = spd*sin(freq*(t-0.075)*(2.*3.141592654));
}
end_f_loop(f, thread)
}


All times are GMT -4. The time now is 09:19.