[Weiqiang Liu]

Hi all,

I am trying to reproduce results in literature. For inlet velocity boundary condition setting, the author says "The inflow velocity distribution is given by the poiseuille flow"

I know poiseuille flow is a parabolic velocity distribution from central to wall. I am wondering how can I set the parameters of this parabolic distribution if I know the central velocity of inflow?

Best regards

Weiqiang

[mCiFlDk]

Originally Posted by Weiqiang Liu

Hi all,

I am trying to reproduce results in literature. For inlet velocity boundary condition setting, the author says "The inflow velocity distribution is given by the poiseuille flow"

I know poiseuille flow is a parabolic velocity distribution from central to wall. I am wondering how can I set the parameters of this parabolic distribution if I know the central velocity of inflow?

Best regards

Weiqiang

Hi weiqiang,


To make that, you've to use a User Defined Function, more specifically a DEFINE_PROFILE one. Luckily, ANSYS has a very similar function in its manual to imitate this problem you're trying to simulate.

/***********************************************************************
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, h;
  face_t f;

  h = 0.016; /* inlet height in m */

  begin_f_loop(f,thread)
  {
    F_CENTROID(x, f, thread);
    y = 2.*(x[1]-0.5*h)/h; /* non-dimensional y coordinate */
    F_PROFILE(f, thread, position) = 0.1*(1.0-y*y);
  }
  end_f_loop(f, thread)
}

Code got from: https://www.afs.enea.it/project/nept...df/node243.htm


If you look a bit deeper in the manual, this will not be very complicated since the function is that and you only have to modify the parameters for your specific case.


Regards.