C_UDMI & C_UDSI problem.
 

I want to run a DEFINE_ON_DEMAND udf in order to save the UDS at the wall in a UDM.
Actualy, I dont have any problem if i save the whole UDS result but i am not able to do it too.

I used the following code:


DEFINE_ON_DEMAND(wall_UDS_value)
{
Domain *d;
face_t f;
cell_t c, c0;
Thread *t,*t0, *c_thread;
int Zone_ID=3; /* Zone ID of the wall on which UDS to be calculated */
/* It can be obtained from the boundary condition panel.*/
d=Get_Domain(1);

/* Initialize the UDM value to zero in complete domain */
thread_loop_c(c_thread,d)
{
begin_c_loop(c, c_thread)
{
C_UDMI(c,c_thread,0)= 0;
}
end_c_loop(c, c_thread)
}

t=Lookup_Thread(d,Zone_ID);
begin_c_loop (c,t)
{
c0 = F_C0(f,t);
t0 = THREAD_T0(t);
C_UDMI(c0,t0,0) = C_UDSI(c,t,0);

}
end_c_loop (c,t)
}


Can anyone help me. What i did wrong?

Thank you for your answer.

Dim

hello dimitrios,

to access the values on a wall, which is, from the geometrical point of view a 2-d plane and in the context of fluent a "face", you need to loop over faces and not cells.
Thus, use something like begin_f_loop and F_UDMI and you wil get what you want.

cheers

Hello Max,
Firstly, thank you very much for your quick reply and help.
I tried what you said but I had some problems. When i used the following code the result is an "ACCESS_VIOLATION".

Could you tell me please if you know something more about that?

DEFINE_ON_DEMAND(wall_UDS_value)
{
Domain *d;
face_t f;
cell_t c;
Thread *t,*t0, *f_thread;
int Zone_ID=3; /* Zone ID of the wall on which UDS to be calculated */
/* It can be obtained from the boundary condition panel.*/
d=Get_Domain(1);
/* Initialize the UDM value to zero in complete domain */
thread_loop_f (f_thread,d)
{
begin_f_loop(f, f_thread)
{
F_UDMI(f,f_thread,0)=0;
}
end_f_loop(f,f_thread)
}

t=Lookup_Thread(d,Zone_ID);
begin_f_loop (f,t)
{
t0 = THREAD_T0(t);
F_UDMI(f,t0,0) = F_UDSI(f,t,0);
}
end_f_loop (f,t)
}

Thank you for your answer.

Dim

if I may throw in my 2 cents. first, f is from thread t, I am NOT sure if you can use it in F_UDMI(f,t0,0). correct me if I am wrong. second, F UDMI is available for wall and
flow boundary faces only and t0 may NOT be either of those.

Hello Ivan,
Thank you very much for your reply.
You are right! Sorry I posted by mistake the wrong udf.

actually i used the following udf with the same "ACCESS_VIOLATION".

DEFINE_ON_DEMAND(wall_UDS_value)
{
Domain *d;
face_t f;
cell_t c;
Thread *t, *f_thread;
int Zone_ID=3; /* Zone ID of the wall on which UDS to be calculated */
/* It can be obtained from the boundary condition panel.*/
d=Get_Domain(1);
/* Initialize the UDM value to zero in complete domain */
thread_loop_f (f_thread,d)
{
begin_f_loop(f, f_thread)
{
F_UDMI(f,f_thread,0)=0;
}
end_f_loop(f,f_thread)
}
t=Lookup_Thread(d,Zone_ID);
begin_f_loop (f,t)
{
F_UDMI(f,t,0) = F_UDSI(f,t,0);
}
end_f_loop (f,t)
}

Any ideas?

Thank you for your answers.
Dim