[D.M]

Hi guys,
anyone knows how can i hook DEFINE_DELTAT in fluent?
i know i should use adaptive time step in the fluent menu and ... but when i hook my udf in that menu and start the calculation nothing happens (it just calculates 1 time step and nothing more!), i want to know if there is anything that i should do before starting calculation or not, here is my udf :

#include "udf.h"
DEFINE_DELTAT(delta_t,d)
{
real time_step;
real flow_time = CURRENT_TIME;
if (flow_time < 0.1)
time_step = 0.001;
else if (flow_time < 0.14)
time_step = 0.0001;
else
time_step = 0.001;
return time_step;
}

[vasava]

Try

if (flow_time >= 0.1 && flow_time < 0.14)
time_step = 0.001;
else 
time_step = 0.0001;
return time_step;
}

[D.M]

Hi vasava,
tnx for the help , i got the point & tried something similar to your code and it really worked , thanks for the help again