[Dh9g12]

Hello,

I am trying to recreate the heaving and pitching motion of a 2D airfoil by the following UDF:

#include "udf.h"
#include <stdio.h>
#include <math.h>

DEFINE_CG_MOTION(airfoilpitch, dt, cg_vel, cg_omega, time, dtime)
{
cg_vel[0] = 0.0;
cg_vel[1] = 2*3.141592654*0.5*cos((2*3.141592654*0.5*time)+(3. 141592654/2));
cg_vel[2] = 0.0;
cg_omega[0] = 0.0;
cg_omega[1] = 0.0;
cg_omega[2] = 0.1745329252*2*3.141592654*0.5*cos(2*3.141592654*0 .5*time);
}

However I am unsure how to go about it in terms of creating the mesh i.e. what mesh methods and settings should be used and also if my mesh is right (See attached). So far I've managed to make the inner circle move in the right motion but it leaves a gap where the mesh should deform (image 3)

Thankyou. Any help/suggestions would be much appreciated!

[Tauseef]

Dear Dh
I think the folling line
cg_vel[1] = 2*3.141592654*0.5*cos((2*3.141592654*0.5*time)+(3. 141592654/2));
is creating this vertical motion of the rotating zone, what it doing is translating the Y componet of the CG location by the value calculated cg_Vel[1].
if you are trying to apply plunge motion better to use the Zone motion UDFs they perform better than CG_Motion UDFs