[psychobob]

Hey all!
Im currently attempting to write a udf for a velocity inlet to turn on and off the volume fraction as a function of time (starting on and pulsing every 5 seconds). Ive tried to cobble together a code from other similar things but I am very inexperienced with C and really am unsure what a lot of the macros and such really mean. Below is what I have for the UDF but I get parsing errors when I try to interpret it and "Error: received a fatal signal (Segmentation fault)." when I tried running it at one point. Any help would be great and thanks ahead of time!

#include"udf.h"
DEFINE_PROFILE(volume_fraction, t, mixture_domain)
{
int phase_domain_index;
cell_t cell;
Thread *cell_thread;
Domain *subdomain;
real time;
time = CURRENT_TIME;
sub_domain_loop(subdomain, mixture_domain, phase_domain_index)
{
thread_loop_c(cell_thread,subdomain)
{
begin_c_loop(cell, t)
if (DOMAIN_ID(subdomain) == 2)
{
if((time=>0) && (time<5))
{
C_VOF(cell,time)=1;
}
if((time=>5) && (time<10))
{
C_VOF(cell,time)=0;
}
if((time=>10) && (time<15))
{
C_VOF(cell,time)=1;
}
if((time=>15) && (time<20))
{
C_VOF(cell,time)=0;
}
if((time=>20) && (time<25))
{
C_VOF(cell,time)=1;
}
}
end_c_loop(cell, time)
}
}
}

[`e`]

The segmentation fault is caused by your variables which are not initialised (including subdomain, mixture_domain and phase_domain_index). Regardless, you shouldn't need to specify domain and thread loops for boundary UDFs, instead these are applied at a certain boundary from the GUI. Try following the logic of this UDF; note that you can use a conditional statement to alternate between on/off instead of specifying all time periods.