udf for 3D laminar fully developed flow

salman

hello,

iam doing my project with titled flow between two stationary plates in the horizontal position.

there is an inlet from the top in the center of the top plate with hole diameter=20mm.

there is a gap of 20mm between two plates and the output is in the radially outward direction.

my inlet direction is perpendicular to the plate that is,in the z-direction.

i need to create a fully developed flow at the inlet.

can you please help me in getting the udf(user defined function) for the fully developed flow at the inlet in 3-dimensional. my z-axis is perpendicular to the x and y-axis.

i got a udf for 3D and iam attaching it below. please look at it and comment on it,whether i will get a laminar fully developed flow profile in the negative z-axis. thanks a lot in advance.

with regards,

salman.......

UDF CODE:

#include<udfconfig.h>

DEFINE_PROFILE(inletvelocity, thread, position) { real x[ND_ND]; /* this will hold the position vector */ real z; face_t f;

begin_f_loop(f, thread)

{

F_CENTROID(x,f,thread);

z = sqrt(pow(x[0],2)+pow(x[1],2));

F_PROFILE(f,thread,position) = 0.04*(1-((z/0.01)*(z/0.01)));

} end_f_loop(f, thread) }