[asking]

Hi,

I wrote a UDF that determines the position and velocity of a body subjected to lift and drag forces. These variables are updated each time step and depend on their previous v(t-1) and current values v(t).

The UDF works as intended when I am running it on fluent. The problem starts when I am trying to restart the simulation after X time steps (i.e. run the simulation for X time step, save the last result, close fluent, load the last saved time step, run the simulation). The velocity value is not saved and goes back to zero when the simulation is restarted.

How can I store these values at the last saved time step so I can use them when I restart the simulation?

Thanks,

[AlexanderZ]

write to file, or use UDMI

best regards

[asking]

Originally Posted by AlexanderZ

write to file, or use UDMI

best regards

Thank you Alexander.

At the beginning I didnt want to use UDMI since I found it that saving a constant value on each cell of the body was quite inefficient but at the end I just did it and it works as intended. In any case... for completeness, this is my implementation.

if (load_ini_UDMI_time < ctime)
{
/*Load UDMI*/
#if !RP_HOST
Thread *t,*t0_cell;
Domain *d = Get_Domain(1);
cell_t c0;
face_t f;
t = Lookup_Thread(d,zoneID);

begin_f_loop(f,t)
{
if (PRINCIPAL_FACE_P(f,t))
{
	c0 = F_C0(f,t);
	t0_cell = THREAD_T0(t);
	
	vxRK = C_UDMI(c0,t0_cell,3);
	vyRK = C_UDMI(c0,t0_cell,4);
	vx = C_UDMI(c0,t0_cell,5);
	vy = C_UDMI(c0,t0_cell,6);
	ax = C_UDMI(c0,t0_cell,7);
	ay = C_UDMI(c0,t0_cell,8);
	}
}
end_f_loop(f,t)
#endif

node_to_host_real_6(vxRK,vyRK,vx,vy,ax,ay);
load_ini_UDMI_time = ctime + 10000;
}

This code will be only executed at the first time-step and it will load the saved constants.

Regards