[ajene]

hello,
I want to calculate the velocity divergence of a specific cell as a source term， but there is
access violation:
Error:
C:\PROGRA~1\ANSYSI~1\v145\fluent\fluent14.5.0\win6 4\2ddp\fl1450s.exe 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: #f





can you give me some advice？ the UDF is as follow:

DEFINE_SOURCE(UDS_s_p2, c_UDS_s_p2,t_UDS_s_p2, ds_UDS_s_p2, eqn_UDS_s_p2)
{
real source_UDS_s_p2;
Thread *mix_t_UDS_s_p2;
Thread *t_UDS_s_liquid_p2;


real NV_VEC(A_TOL),NV_VEC(VEC),NV_VEC(VEC0),NV_VEC(VEC1 ),NV_VEC(A);
real div_V;
Thread *tf;
int f,n;
cell_t c0, c1 = -1;
Thread *t0, *t1 = NULL;


source_UDS_s_p2=0.0;
div_V=0;
mix_t_UDS_s_p2=THREAD_SUPER_THREAD(t_UDS_s_p2);
t_UDS_s_liquid_p2= THREAD_SUB_THREAD(mix_t_UDS_s_p2, 0);

c_face_loop( c_UDS_s_p2, mix_t_UDS_s_p2,n) /*loop the faces of a specific cell*/
{
f=C_FACE( c_UDS_s_p2,mix_t_UDS_s_p2,n); /* retrive the ID of face on liquid level */
tf=C_FACE_THREAD( c_UDS_s_p2,mix_t_UDS_s_p2,n); /* retrive the thread of face on liquid level */

c0 = F_C0(f,tf);
t0 = F_C0_THREAD(f,tf);
F_AREA(A,f,tf);
if (BOUNDARY_FACE_THREAD_P(tf))
{
NV_D(VEC,=,F_U(f,tf),F_V(f,tf),F_W(f,tf));
}

else
{
c1 = F_C1(f,tf);
t1 = F_C1_THREAD(f,tf);
NV_D(VEC0,=,C_U(c0,t0),C_V(c0,t0),C_W(c0,t0)) ;
NV_D(VEC1,=,C_U(c1,t1),C_V(c1,t1),C_W(c1,t1));
NV_VS_VS(VEC,=,VEC0,*,0.5,+,VEC1,*,0.5);
}
div_V+=NV_DOT(A,VEC); /* intergration of area dot velocity for all the faces in the cell */
}

div_V/=C_VOLUME(c_UDS_s_p2,mix_t_UDS_s_p2);

source_UDS_s_p2 =+ div_V;
}

ds_UDS_s_p2[eqn_UDS_s_p2]=0.0;
return source_UDS_s_p2;
}