Many thanks in advance for your help.

#include "udf.h"

#include "mem.h"

#include "unsteady.h"

DEFINE_PROFILE(pressure_outlet4, thread, index)

{

face_t f;

real p,p1,p2;

real t = CURRENT_TIME;

real dt = CURRENT_TIMESTEP;

real area[ND_ND];

real total_area;

real total_flux;

Thread *t0;

cell_t c0;

begin_f_loop(f, thread)

{

double CC,R;

double k1,k2,k3;

k1=2;

k2=-22.53;

k3=8.65;

F_AREA(area,f,thread);

total_area +=NV_MAG(area);

total_flux +=F_FLUX(f,thread);

t0 = THREAD_T0(thread); /* adjacent cell thread to f */

c0 = F_C0(f, thread);

p1=C_P(c0,t0);

C_UDMI(c0,t0,0)=C_P_M1(c0,t0);

CC=1.5*total_area/(k1*exp(k2*sqrt(total_area/M_PI))+k3);

R=8*0.0035*17.73*0.001/(total_area*total_area/M_PI);

p=-R*CC*(p1-C_UDMI(c0,t0,0))/dt+R*ABS(total_flux)/1050;

F_PROFILE(f, thread, index)=p;

}

end_f_loop(f, thread)

}