Using UDF as a boundary condition.

e.g. From user guide:

"#include" udf.h "

DEFINE_PROFILE (pressure_profile, t, i)

{

real x [ND_ND]; / * this will hold the position vector * /

real y;

face_t f;

begin_f_loop (f, t)

{

F_CENTROID (x f, t);

y = x [1];

F_PROFILE (f, t, i) = 1.1e5 - y * y / (. 0745 * .0745) * 0.1e5;

}

end_f_loop (f, t)

}

"

Good answer by Bela. UDF is needed for the velocity profile.

As mentioned above, you should use a UDF function.By googling, you should find some important information and useful functions !