Learning Forum

[sidjou]

Hi Dr Amine,

I'm interested in the position of the plate while using an udf file to put the plate in motion .

From the collected position of the plate, i noticed that at t=0, the plate is not exactly at the known center of gravity of 6.25e-5 m and the plate has the same position (1.23e-4 m) for 2 consecutive times step (24 & 25).

How can i correct it please? I want to have the exact known center of gravity (6.25e-5 m) at t=0 and expect different position at time step 24 and 25. Below are the report of the plate position and the udf code. Thanks!

 

/* UDF for specifying a sinusoidal motion */

#include "udf.h"

#define amp RP_Get_Input_Parameter("amplitudeid")
#define freq RP_Get_Input_Parameter("frequencyid")
#define angular_freq 2.0*M_PI*freq

DEFINE_CG_MOTION(movingplate, dt, cg_vel, cg_omega, time, dtime)
{
    real disp;
 
  disp = amp*angular_freq*cos(angular_freq*time); /*displacement speed*/

  cg_vel [0] = 0.0;
  cg_vel [1] = 0.0;
  cg_vel [2] = disp;
 
  cg_omega [0] = 0.0;
  cg_omega [1] = 0.0;
  cg_omega [2] = 0.0;
}