[shish99]

my model is an outer sphere enclosing an inner sphere, separated by fluid, so 2 walls and a fluid. My question is how can I vibrate the inner sphere at 3 m/s in the translation directions stated by arrows, while the inner sphere won't touch the outer sphere after vibrating. so the inner sphere should move upwards, downwards, left and right as if vibrating.
ANSYS FLUENT

[aero_head]

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)
}