When I activate DEFINE_ON_DEMAND --> "received fatal signal (ACCESS_VIOLATION)"
 

Dear all,

I'm working in the simulation of snowdrift.I have problems in my UDF.When i activate the DEFINE_ON_DEMAND macro ,the following error will occur:
FLUENT received fatal signal (ACCESS_VIOLATION)
1. Note exact events leading to error.
2. Save case/data under new name.
3. Exit program and restart to continue.
4. Report error to your distributor.
Error Object: ()

This is my UDF of the volume fraction in boundary condition and computing the erosion and deposition of snow.

#include"udf.h"
#define zo 1
#define uo 5
#define ps 150
#define uxt 0.15
#define zs 0.00003
#define af 0.25
#define wf 0.2

/*PROFILE FOR VOLUME FRACTION*/
DEFINE_PROFILE(volume_fraction,thread,index)
{
real x[ND_ND];
real z,um,ux,hs;
Thread**pt;
cell_t c;
begin_c_loop(c,thread)
{
C_CENTROID(x,c,thread);
z=x[2];
um=uo*pow((z/zo),af);
ux=um*0.4/log(z/zs);
hs=0.8*ux*ux/9.8;
if(z<=hs)
{
F_PROFILE(c,thread,index)=0.8*exp(-1.55*(4.78*pow(ux,-0.544)-pow(z,-0.544)))/ps;
}
else
{
F_PROFILE(c,thread,index)=0.68*uxt*(ux*ux-uxt*uxt)/ux/uxt/22.54;
}
}
end_c_loop(c,thread)
}

/*DEMAND FOR COMPUTE EROSION AND DEPOSITION*/
DEFINE_ON_DEMAND(on_demand_calc)
{
Domain*d;
real x[ND_ND];
real z,um,ux,hs,vof;
Thread*t;
cell_t c;
d=Get_Domain(1);
thread_loop_c(t,d);
begin_c_loop(c,t)
{
C_CENTROID(x,c,t);
z=x[2];
um=uo*pow((z/zo),af);
ux=um*0.4/log(z/zs);
hs=0.8*ux*ux/9.8;
C_VOF(c,t);
if(z<=hs)
{
vof+=0.8*exp(-1.55*(4.78*pow(ux,-0.544)-pow(z,-0.544)))/ps;
}
else
{
vof+=0.68*uxt*(ux*ux-uxt*uxt)/ux/uxt/22.54;
}
}
end_c_loop(c,t)
printf("\n VOF=%g \n",vof);
begin_c_loop(c,t)
{
if(ux<=uxt)
{
C_UDMI(c,t,0)=wf*ps*vof*(uxt*uxt-ux*ux)/uxt/uxt;
}
else
{
C_UDMI(c,t,1)=0.0007*(uxt*uxt-ux*ux);
}
}
end_c_loop(c,t)
}

This UDF can be interpreted,but i can't solve and calculate with it.

I just start to learn the FLUENT software and i don't know how to modify the UDF,especially in the DEFINE_ON_DEMAND macro.

I'm very grateful for someone can help me with the modifying of UDF or point out that the basic mistake.

In badly need of help
 

Please help me with my UDF.
Thanks for you in advance.:)

Why
 

Why no one to help me?You can just point out the basic error.Thanks.