[YFUO28]

hey,

For transient simulation of oscillating 2D airfoil I am using dynamic mesh. The airfoil need to oscillating between -5deg to 5deg.

The change of the angle of attack define by UDF file.

this is the UDF I wrote:
/************************************************** ********************
UDF for specifying a transient Oscillating 2D Airfoil
************************************************** *********************/

#include "udf.h"
#define Freq 0.0527
#define angular_freq 2.0*M_PI*Freq
#define tetmax (5.0-(-5.0))*M_PI/180

DEFINE_CG_MOTION(shm, dt, cg_vel, cg_omega, time, dtime)
{
real omega;

omega = tetmax*angular_freq*cos(angular_freq*time);

cg_vel[0] = 0.0;
cg_vel[1] = 0.0;
cg_vel[2] = 0.0;

cg_omega[0] = 0.0;
cg_omega[1] = 0.0;
cg_omega[2] = omega;
}



Now when I check the motion with DISPLAY ZONE MOTION in the fluent (inside the dynamic mesh task page) the airfoil moving only on the positive side of omega.

someone can say what wrong with me UDF file or something I need to change?

Thx for the help.

[YFUO28]

Ok, I find what wrong. the equation in time 0 start at 5 deg and then the range of the angle of attack between 0 deg to 10 deg.

Someone know who to fix this? who the airfoil start in time 0 at angle of 0 deg?