[Bruno Machado]

Hi all,

I am trying without success to implement the DEFINE_UDS_FLUX macro for a UDS I am solving in my problem. I have a function defined as C_FUNCTION(c,t), which defines the density of my scalar in a cell base. Nevertheless, I have no idea how to define it with respect of the face (e.g. C_R/F_R).

I've got this piece of code from Fluent manual, replaced with the C_FUNCTION, but I have no idea what to use for the face line (???).

Can someone help me with this task?

Thank you very much in advance.

DEFINE_UDS_FLUX(my_uds_flux,f,t,i)
{
  cell_t  c0,  c1 = -1;
  Thread *t0, *t1 = NULL;

  real NV_VEC(psi_vec), NV_VEC(A), flux = 0.0;

  c0 = F_C0(f,t);
  t0 = F_C0_THREAD(f,t);
  F_AREA(A, f, t);

  
  /* If face lies at domain boundary, use face values; */
  /* If face lies IN the domain, use average of adjacent cells. */

 if (BOUNDARY_FACE_THREAD_P(t)) /*Most face values will be available*/
    {
      real dens0, dens1;

      /* Depending on its BC, density may not be set on face thread*/
      if (NNULLP(THREAD_STORAGE(t,SV_DENSITY)))

	  dens0 =??? ; /*F_R(f,t) Set dens to face value if available */

      else
      dens0 = C_FUNCTION(c0,t0); /* else, set dens to cell value */

      NV_DS(psi_vec,  =, F_U(f,t), F_V(f,t), F_W(f,t), *, dens0);

      flux = NV_DOT(psi_vec, A); /* flux through Face */
    }
  else
    {
      c1 = F_C1(f,t);       /* Get cell on other side of face */
      t1 = F_C1_THREAD(f,t); 

	  dens0 = C_FUNCTION(c0,t0);
	  dens1 = C_FUNCTION(c1,t1);

      NV_DS(psi_vec,  =, C_U(c0,t0),C_V(c0,t0),C_W(c0,t0),*,dens0);
      NV_DS(psi_vec, +=, C_U(c1,t1),C_V(c1,t1),C_W(c1,t1),*,dens1);

      flux = NV_DOT(psi_vec, A)/2.0; /* Average flux through face */
    }

  /* ANSYS FLUENT will multiply the returned value by phi_f (the scalar's
     value at the face) to get the "complete'' advective term.  */

  return flux;
}

[pakk]

It looks like you will have to define a function (I propose with name F_FUNCTION(f,t)) that defines the density of your scalar on faces.

I have no idea what you did with C_FUNCTION, but you should probably try to make F_FUNCTION physically consistent.