[houssame222]

Hi, As I just started using fluent, I am looking for someone who has or at least can help me to turn this code into a 3D code, In fact, I have found the 2D parabolic profile but as my simulation are in 3D, I will need a 3D profil ...

/* vprofile.c */
/* UDF for specifying steady-state velocity profile boundary condition */
/************************************************** *********************/
#include "udf.h"
DEFINE_PROFILE(inlet_x_velocity, thread, position)
{
real x[ND_ND]; /* this will hold the position vector */
real y;
face_t f;
begin_f_loop(f, thread)
{
F_CENTROID(x,f,thread);
y = x[1];
F_PROFILE(f, thread, position) = 20. - y*y/(.0745*.0745)*20.;
}
end_f_loop(f, thread)
}

Thanking you ..

[mprinkey]

It is not very complicated. I can't give you a complete answer, because I don't know how your inlet is oriented. I've made a few changes to your code. Xf[] is the face centroid vector. x,y,z are the coordinates picked out of that vector. So, that is easy access to your location data. Then you just need to change the F_PROFILE function line to match your boundary conditions using the x, y, and/or z coordinates.

/* vprofile.c */
/* UDF for specifying steady-state velocity profile boundary condition */
/***********************************************************************/
#include "udf.h"
DEFINE_PROFILE(inlet_x_velocity, thread, position)
{
real Xf[ND_ND]; /* this will hold the position vector */
real x,y,z;
face_t f;
begin_f_loop(f, thread)
  {
  F_CENTROID(Xf,f,thread);
  x = Xf[0];
  y = Xf[1];
  z = Xf[2];
  F_PROFILE(f, thread, position) = 20. - y*y/(.0745*.0745)*20 - z*z/(....);
  }
end_f_loop(f, thread)
}

[FMDenaro]

It is not clear to me if you have a full confined 3D inflow or a 2D profile to repeat periodically in spanwise direction

[houssame222]

Originally Posted by mprinkey

It is not very complicated. I can't give you a complete answer, because I don't know how your inlet is oriented. I've made a few changes to your code. Xf[] is the face centroid vector. x,y,z are the coordinates picked out of that vector. So, that is easy access to your location data. Then you just need to change the F_PROFILE function line to match your boundary conditions using the x, y, and/or z coordinates.

/* vprofile.c */
/* UDF for specifying steady-state velocity profile boundary condition */
/***********************************************************************/
#include "udf.h"
DEFINE_PROFILE(inlet_x_velocity, thread, position)
{
real Xf[ND_ND]; /* this will hold the position vector */
real x,y,z;
face_t f;
begin_f_loop(f, thread)
  {
  F_CENTROID(Xf,f,thread);
  x = Xf[0];
  y = Xf[1];
  z = Xf[2];
  F_PROFILE(f, thread, position) = 20. - y*y/(.0745*.0745)*20 - z*z/(....);
  }
end_f_loop(f, thread)
}

I thank you for your answer, indeed, my inlet is normal to the x direction and the profile of the velocity vectors is depending just on z that means that it is a 2D flow in 3D geometry
I have this but it still doesn't work ...

/* vprofile.c */
/* UDF for specifying steady-state velocity profile boundary condition */
/************************************************** *********************/
#include "udf.h"
DEFINE_PROFILE(inlet_x_velocity, thread, position)
{
real x[ND_ND];
real z;
face_t f;
begin_f_loop(f, thread)
{
F_CENTROID(x,f,thread);
z = x[2]-0.6095;
F_PROFILE(f, thread, position) = 20*(1.0 - z * z / (0.6095*0.6095));
}
end_f_loop(f, thread)
}

[houssame222]

Originally Posted by FMDenaro

It is not clear to me if you have a full confined 3D inflow or a 2D profile to repeat periodically in spanwise direction

Hi, Denaro, thank you for ur answer, indeed, it is a 2D profile in a 3D geometry, as I said, I inlet is normal to the x direction and the velocity depends on z,
/* vprofile.c */
/* UDF for specifying steady-state velocity profile boundary condition */
/************************************************** *********************/
#include "udf.h"
DEFINE_PROFILE(inlet_x_velocity, thread, position)
{
real x[ND_ND];
real z;
face_t f;
begin_f_loop(f, thread)
{
F_CENTROID(x,f,thread);
z = x[2]-0.6095;
F_PROFILE(f, thread, position) = 20*(1.0 - z * z / (0.6095*0.6095));
}
end_f_loop(f, thread)
}

it still doesn't want to work I don't have a parabolic profile at the inlet and I don't understand why,
for the inlet, it is defined between z=0 to z=1.2
I really don't know why..