[mooby]

Hi,
I am doing a simulation for pitching of an airfoil using Fluent 15.0
I have an equation Alpha(t) = alpha0 + alpha_amp*sin(wt) which i differentiate it with respect to time to obtain angular frequency. My UDf is given below:
#include "udf.h"
/*#include <stdio.h>
#include <math.h>*/
DEFINE_ZONE_MOTION(motion,omega,axis,origin,veloci ty,time,dtime)
{ FILE *fp; /* Declaring file variable */

real thz,alpha;
alpha1 = 11+ (11*sin(4.335*time));/*Calculating AOA by method 1*/
/* record the kinematic data in the file */
fp = fopen("Alpha.txt", "a"); /* Open a file to data to the end */

*omega= (0.0175*11*4.335*cos(4.335*time));
alpha2=*omega * (CURRENT_TIME );/*Calculating AOA by method 2*/
printf("time(sec) = %f, Omega(Rad/sec) = %f, AOA (Deg.) = %f, AOA (Deg.) = %f\n", time, *omega,alpha1,alpha2);

fprintf(fp,"%f, %f, %f\n", time, *omega,alpha1);


fclose(fp); /* Closing the file */

return;

}

My alpha0 = 11 Deg, so I have fixed my Airfoil at 11 Deg AoA. The mesh motion is fine but what I dont get is correct AOA when I use equation above in my UDF to calculate AOA. Calculated AOA by above two methods in UDF does not corresponds to the orientation of airfoil in the pictures I save.

Any help will be appreciated

Could you please help me