[ronak]

Hi
I'm simulating a flapping airfoil. I mean pitching and heaving by flapping. I've been using this UDF:


#include "udf.h"
DEFINE_CG_MOTION(airfoil,dt,vel,omega,time,dtime)
{
Thread *t;
face_t f;
real w,a,h, pi,fi;
pi = 3.14159265;
h= 0.5; /*Heave amplitude*/
a = (pi*15)/180; /*pitch amplitude*/
w = 1.168; /*angulat velocity*/
fi =(pi*90)/180 ; /*phase difference*/


/*get the thread pointer for which the motion is defined*/
vel[1] = h*w*cos(w*time);
omega[2]=a*w*cos(w*time+fi);

}
this UDF is defined for airfoil in dynamic mesh zone.

Is it the proper user defined function for a flapping motion?
Thanks in advance

[Ahmed Saeed Mansour]

Hello dear Hanye, use this :

/**********************************************/
/* flap.c */
/* UDF for specifying a time-varying omega */
/* */
/* Simulates +/- 8 deg flapping with cycle of */
/* of 1 sec. */
/* */
/* Version 13.0 */
/* */
/**********************************************/
#include "udf.h"
#define PI 3.141592654
DEFINE_TRANSIENT_PROFILE(speed, time)
{
real ampl = 2.0*PI/15.0;
real freq = 2.*PI;
real omega;

omega = 2.0*PI*ampl*cos(freq*time);
return omega;
}

[ronak]

@Philip_Morris
I've used this UDF and it is propper for a flapping motion. Airfoil pitches and plunges at the same time.
Hope it helps

[Ahmed Saeed Mansour]

Originally Posted by ronak

@Philip_Morris
I've used this UDF and it is propper for a flapping motion. Airfoil pitches and plunges at the same time.
Hope it helps

Thanks dear Philip, here is my tutorial about the flapping airfoil:
https://youtu.be/5pltEzl2-J8
Danke!