UDF编译出现FLUENT received fatal signal (ACCESS_VIOLATION)

xupp89

UDF编译出现FLUENT received fatal signal (ACCESS_VIOLATION)  
我做得是模拟管内水流动换热，通过UDF定义不均匀的热流分布。想得到壁面温度，用于计算辐射和对流损失，可是初始化就会出现：
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.
请各位帮忙指出问题所在啊！感谢！
#include "udf.h"
#include "mem.h"
#include "math.h"

real q0=8410.7183;
real zc=0.0000000000000000000874019;
real w=0.04086;
real A=5460.56552;
real siga=0.00000005672;
real Ta=273.0;

DEFINE_PROFILE(heat_profile,thread,position)
{
    real x[ND_ND];         
    real a;
    real b;
    real c;
    face_t f;
    real T;
    face_t t;
   T=F_T(f,t);//想得到壁面温度，用于计算辐射损失与对流损失
    begin_f_loop(f,thread)
    {
        C_CENTROID(x,f,thread);
        a=x[0];
        b=x[1];
        c=x[2];
        if(b>=0.0)
        {
                        F_PROFILE(f,thread,position)=(q0+(A/(w*sqrt(M_PI/2.0)))*exp(-2.0*pow((c-zc)/w,2.0)))*(b/sqrt(a*a+b*b))-siga*(pow(T,4.0)-pow(Ta,4.0))-0.5*(T-Ta);
        }
    end_f_loop(f,thread)
}