[bensciens]

Hello,

I've been trying to write a FLUENT UDF which cycles through all the cells in my FLUENT case. For each cell I want to loop over all the faces and calculate something using the face temperature. However, when the code reaches 'temp=F_T(f,tf)' I get a segmentation fault. I'm fairly new to the UDF stuff so I'm struggling to find the error.

I am trying to make this work on FLUENT 17.2 and the case models the transonic, viscous 2D flow over the NACA0012 aerofoil. Here is a minimal code example which throws the segmentation fault:

#include "udf.h"
#include "mem.h"
#include "sg.h"
#include "math.h"

DEFINE_ON_DEMAND(shock_viscous3)
{
    Domain *d;
    cell_t c;
    Thread *tf;
    face_t f;
    Thread *t;
    int n;
    
    real A[ND_ND];
    real f_visc, temp;

    d=Get_Domain(1);
    Message("Entering loop\n");

    thread_loop_c(t,d)
    {    // looping over cells 
        begin_c_loop(c,t)
        {                
            f_visc= (C_MU_L(c,t)+C_MU_T(c,t))/C_MU_L(c,t);
            if (f_visc > 15.0)
            {
                c_face_loop(c, t, n)         /* loops over all faces of a cell */
                {
                    f = C_FACE(c,t,n);
                    tf = C_FACE_THREAD(c,t,n);
                    Message("Temp\n");
                    temp=F_T(f,tf);
                    Message("After Temp\n");
                }
            }
        }
        end_c_loop(c,t)
    }
}

Any help would be greatly appreciated.

[LuckyTran]

Did you declare temp in the UDM beforehand?