[sanjay]

hi,
I am working on synthetic jet flow simulation. I am planning to compare the effect of moving wall (Dynamic mesh) with the sinusoidal velocity input. Can anyone help me with compiling the udf and running this case. This is a 2D case model.

[sadegh1068]

Hi dear sanjay,
you can this UDF.
this is a sample code for a diaphragm deformation. you can set it for your geometry.

DEFINE_GRID_MOTION(moving_arc, domain, dt, time, dtime)
{
  Thread *tf = DT_THREAD (dt);
  face_t f;
  Node *node_p;
  real alpha, theta, x, ymag, yfull, y;
  int n;
  
/* Set/activate the deforming flag on adjacent cell zone, which      */
/* means that the cells adjacent to the deforming wall will also be  */
/* deformed, in order to avoid skewness.                             */
  SET_DEFORMING_THREAD_FLAG (THREAD_T0 (tf));

/* Compute the angles:                                               */
  alpha = omega * CURRENT_TIME;
  theta = 2.0 * alpha + 3.0 * M_PI / 2.0;
  
/* Loop over the deforming boundary zone's faces;                    */
/* inner loop loops over all nodes of a given face;                  */
/* Thus, since one node can belong to several faces, one must guard  */
/* against operating on a given node more than once:                 */

  begin_f_loop (f, tf)
    {
      f_node_loop (f, tf, n)
        {
          node_p = F_NODE (f, tf, n);

          /* Update the current node only if it has not been         */
          /* previously visited:                                     */
          if (NODE_POS_NEED_UPDATE (node_p))
            {
              /* Set flag to indicate that the current node's        */
              /* position has been updated, so that it will not be   */
              /* updated during a future pass through the loop:      */
              NODE_POS_UPDATED (node_p);

              x     = NODE_X (node_p);
              ymag  = sqrt (R*R - x*x) + 0.03;
              yfull = ymag - 0.1;
              y     = - 0.1 + yfull * sin(theta);
              NODE_Y (node_p) = y;
            }
        }
    }
  end_f_loop (f, tf);

use "user define" in the dynamic mesh panel.
Note that this is a 2-D UDF code.

[sanjay]

Hi,
Thanks a lot for the code. I will compile it.

[anon_m]

Hello:

Regarding this post (I know it's from some time ago), I am wondering if you had any problems with negative cell volume and if so how you solved it.

Thank you.

[sanjay]

Hi,
am facing the problem of negative cells.

[iec]

hi dear sanjay,
can you accomplish with this code.

I have skimmed this code but no have a dimensions to moving arc. How do works this code