[heaven1]

Hi all,

I'm working on an axisymmetric model with swirl. I want to extract the velocities on the wall to calculate a partial slip shear stress. I'm using the UDF as shown below to extract the velocities on the wall, and this works when there is full stick at the walls. However when I change the boundary condition on the walls to a shear stress condition the F_W function returns the last result it found which is not correct if I compare them to the velocity plots of fluent.

The F_U and F_V function do give me the correct velocities.

Can I not use the F_W function with axisymmetric models with swirl or could this be a bug from fluent itself?

DEFINE_ON_DEMAND(vel_sub_face)
{
  int ID = ID_sub; // Plate ID
  Domain *d = Get_Domain(1); // Fluid ID
  Thread *t = Lookup_Thread(d,ID);
  face_t f;

  real fc[ND_ND];

  begin_f_loop(f,t)
  {
    F_CENTROID(fc,f,t);
    Message("y=%e \tvx=%e \t vy=%e \t vz=%e \n",fc[1],F_U(f,t),F_V(f,t),F_W(f,t));
  }
  end_f_loop(f,t)
  Message("velocity substrate on the face\n");
}

I’m using FLUENT 2019 R3 btw.