[CaptainCombo]

Hi everybody,

I am trying to simulate flow in heated flat channel while inlet velocity changes according to formula below.

Uin = Uo*[1+Ao*sin(w*t)]

Here;

Uin: inlet velocity
Uo: avarage inlet velocity
Ao: dimensionless pulsation amplitude
w = (2*pi*f)
f : frequency of pulsation
t: time

The program updates velocity profile via compiled UDF. Here is the source code;

#include "udf.h"

DEFINE_PROFILE(pulsating_velocity, t, nv)
{
face_t f;

real flow_time = RP_Get_Real("flow-time");

real PI = 3.141592;

real vel;

begin_f_loop(f,t)
{
F_PROFILE(f,t,nv) = (0.1*(1+1*sin(2*PI*flow_time)));
}
end_f_loop(f,t)

printf("Time =%f sec. \n", flow_time);
printf("Target velocity set at ")
}

The problem is: for every 3th (sometimes 4th) time steps simulation is pausing. During these pausing sequences I observed that cpu usage drops to 10%. It rises to 90% again when calculation of new time step is started. I am not sure whether this is a problem or not but this situation increases total calculation time very much. This is what happens when simulation is paused:

https://www.dropbox.com/s/pr2adqk4or...07.36.png?dl=0

[CaptainCombo]

Problem solved after removing lines below;

printf("Time =%f sec. \n", flow_time);
printf("Target velocity set at ")