what wrong with my udf?
 

#include"udf.h" #define BOLTZ 1.380622e-23 #define AM 4.65e-26 #define AD 4.17e-10 #define PI 3.141592654 #define TMAC 1.0 #define TWALL 300. #define R 297. #define CP 1040.67 #define GAMA 1.40 DEFINE_PROFILE(wallslipdown,thread,index) { real mu,k,AA,Pr,BB; face_t f; cell_t c; Thread *cell_thread; begin_f_loop(f,thread) {c=F_C0(f,thread); cell_thread=THREAD_T0(thread); mu=5.*sqrt(fabs(AM*BOLTZ*F_T(f,thread)/(PI+1.e-50)))/( 16.*AD*AD+1.e-50); k=75.*BOLTZ*sqrt(fabs(BOLTZ*F_T(f,thread)/(AM*PI+1.e-30)))/ (64.*AD*AD+1.e-30); AA=(2.-TMAC)*mu/(TMAC*F_R(f,thread)*sqrt(2.*R*TWALL/PI)); Pr=CP*mu/k; BB=0.75*k*Pr*(GAMA-1)/(GAMA*F_R(f,thread)*R*TWALL); F_PROFILE(f,thread,index)=AA*C_DUDY(c,cell_thread) +BB*C_T_G(c,cell_thread)[0]; } end_f_loop(f,thread) }

I use this udf to define slip velocity in microchannel flow,but when the flow field was initialized,there were "ACCESS VIOLATION "errors.who can help me? My dear friends. Thanks in advance.