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-   -   dynamic mesh and udf problem (http://www.cfd-online.com/Forums/fluent/47043-dynamic-mesh-udf-problem.html)

boboroo January 17, 2008 02:57

dynamic mesh and udf problem
 
I want to simulate a tank with 60% water in it. The tank sways in a changeable omega value which changes with time. The swirl axis is y.

I use the vof modle, and write an udf as follows, set the omega relation and compile it into my fluent case. Then I set the wall of the tank with this udf in "define " dynamic mesh- zone".

Ps: in " define-boundary conditions ", because there is the udf to define its motion so I set the walls of the tank stationary as default.

But after I iterate for some steps, the water in the tank sways but the tank itself doesn't. Who could tell me what the problem in my work? Why the wall were stationary but the water sloshed? And whether my udf below is right? Thanks very much.

# include "udf.h"

DEFINE_CG_MOTION(swaytank, dt, vel, omega, time, dtime)

{ Thread *tf = DT_THREAD (dt);

face_t f;

real NV_VEC (axis);

int n;

/* set the swirl axis*/

NV_D (axis, =, 0.0, 1.0, 0.0);

begin_f_loop (f,tf)

{

/*set the omega relation*/

omega[1] = 0.21 * 0.26 * cos (0.21 * time);

}

end_f_loop (f, tf); }


boboroo January 20, 2008 22:26

Re: dynamic mesh and udf problem
 
anybody could give me some suggestion?


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