My work is in an Oscilating water column and I would like to know how to avoid the negative volumes. when I start my iteration, doing time step.

I tried first with a simple square and it din´t work also I'm not sure if it's my UDF or something else. Another problem is that I can´t define a loop in the UDF using CG_motion and that would desired also. I can thow define the loop in the define_profile

Here is my UDF:

#include "udf.h" # include "dynamesh_tools.h"

/* constants */

#define UMAX 2.82 #define PERIODO 10.0

/* evolução sinosoidal da velocidade */

DEFINE_CG_MOTION(unsteady_veloc, dt, vel, omega, time, dtime) { real t, w_inst; face_t f;

NV_S(omega, =, 0.0); NV_S(vel, =, 0.0);

t = RP_Get_Real("flow-time"); w_inst = 1+UMAX*sin(6.2832*t/PERIODO-1.5708);

}

#include "udf.h"

# include "dynamesh_tools.h"

/* constants */

#define UMAX 2.82

#define PERIODO 10.0

/* evolução sinosoidal da velocidade */

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

{

real t, w_inst;

face_t f;

NV_S(omega, =, 0.0);

NV_S(vel, =, 0.0);

t = RP_Get_Real("flow-time");

w_inst = 1+UMAX*sin(6.2832*t/PERIODO-1.5708);

}