[msd]

Hello All,

I am trying to write a UDF for the pressure outlet boundary condition and the underlying condition is,
P = R*Q.
P = Mean pressure at the outlet (i.e. it remains constant at the whole face)
R = constant taken from literature
Q = flow rate
At the inlet, the pressure boundary condition is specified.

The code written goes as follows,
#include "udf.h"

#define R 12e9 /*Value taken from literature*/

#include "mem.h"
#include "metric.h"

DEFINE_PROFILE (outlet_pressure, thread, position)
{
real A[ND_ND];
face_t f;
Thread *t;
real Ar, V, Qfinal;
real Q = 0;

begin_f_loop(f, thread)
{
F_AREA(A, f, thread);
Ar = NV_MAG(A); /* Used for the computation of the magnitude of the area vector */
V = F_U(f, thread);
Q = Q + (Ar*V);
}
end_f_loop(f, thread)

Qfinal = Q;

begin_f_loop(f, thread)
{
F_PROFILE(f, thread, position) = R*Qfinal;
}
end_f_loop(f, thread)
}


Can someone please tell if there is some logical error in the code because the relation P = R*Q is not getting satisfied.

Thanks in advance!