[HHOS]

Hello,

I have a very easy to picture 2D case. Two flat plates pushing together some fluid drop. One plate is stationary and the other is pressing with a constant force.



I have tried to solve it in two different ways.

The first, which should be the easier one, defining in fluent a spring only with a preload value. It didn't work.

On my second approach, I used the following UDF.

#include "udf.h"

DEFINE_SDOF_PROPERTIES(force_stamp, prop, dt, time, dtime)
{
	prop[SDOF_LOAD_F_X] = 0;
	prop[SDOF_LOAD_F_Y] = -500;
	prop[SDOF_LOAD_F_X] = 0;
	
	prop[SDOF_MASS] = 1;
	prop[SDOF_IXX]  = 0;
	prop[SDOF_IYY]  = 0;
	prop[SDOF_IZZ]  = 0;

   	prop[SDOF_ZERO_TRANS_X] = TRUE;
	prop[SDOF_ZERO_TRANS_Z] = TRUE;
	prop[SDOF_ZERO_ROT_X] = TRUE;
	prop[SDOF_ZERO_ROT_Y] = TRUE;
	prop[SDOF_ZERO_ROT_Z] = TRUE;

   printf ("\n2d_test_box: Updated 6DOF properties");
}

I know that the dynamic mesh options are correct, because I already moved the wall with a velocity profile.

In both cases I defined a mass of 1 kg, because it gives an error with a mass of 0.

I hope somebody can give me a hand here.

Thanks.

[saifullahkhalid]

As a = F/m, putting m = 0 will obviously generate an error in calculating the translatory motion parameters.