[kuldeepnitb@gmail.com]

UDF problem
I am doing the similar kind of study as posted in the forum. I created simple cylinders in the Ansys geometry. Next I created the cylinder geometry then I meshed it (hexa mesh). After creating the mesh I gave name “input” to one end of cylinder and “output” to other end of the cylinder. I gave “name” surface of curvature part of cylinder. I called this meshed geometry in fluent setup.
I have to study the heat generation from the cylinder. Which is function of temperature and pressure of the cylinder? I wrote udf for calculating the heat generation from the cylinder. The udf is interpreted successfully. My udf and case files both are in same directory. In my udf I am using command temp=C_T(c, t); and Pg=C_P(c, t) to obtain the temperature and pressure value from the respective zone, while defining my thread pointer I am using the t=lookup _Thread (d, zone); command. I am testing my udf line by line. But somehow I am getting the access violation error. In the fluent setup window, in boundary condition panel there are only four zone id are written as inlet is 5, outlet id is 6, interior solid is 1 and surface id is 7.
I am applying my udf source file on surface which has zone id 7. I am using the energy model to solve my problem.



Here is my simplified udf code is

DEFINE_EXECUTE_AT_END (source_calculation)
{
Domain *d;
Thread *t;
cell_t c;
real time = CURRENT_TIME;
real temp, Pg, abrate, Peqa, Peqd, mab, mde, m;
real xc[ND_ND];
int zone=7;
d = Get_Domain(1);
t=Lookup_Thread(d,zone);
begin_c_loop(c,t)
{
temp=C_T(c,t);
Pg=C_P(c,t);
m=mab;
}
end_c_loop(c,t);
}

Error message

Here I am giving the same zone ID =7 (WHICH IS WALL), where I hooking my udf source file. Domain id i define is 1. But still I m facing problem. I have tried all the permutation and combination to get of this problem but still I am facing the same problem. When I am using the constant values of temperature and pressure instead of commands temp=C_T(c, t); and Pg=C_P(c, t), then solution initialization is done successfully. It is clear that I am making mistake with t=Lookup_ Thread (d, zone); command but where I am doing mistakes I don’t know. I am very confused, where I am going wrong to solve this basic problem. Am I making very fundamental mistake to solve my problem?