[denis Kim]

Hello,
now i am trying to simulate the sinusoidal rotation of the cylindrical tank with below conditions.

-Amplitude: 50deg (0.872 rad)
-frequency: 0.125 hz (=period: 8sec)

The tank will be simulating with Y axis and there is no transitional movements.
The code what i did is,

#include "udf.h"
DEFINE_ZONE_MOTION(rotation,omega,axis,origin,velo city,time,dtime)
{

*omega[0] = 0.0;
*omega[1] = 2*3.141592*0.125*0.872*cos(2*3.141592*0.125*time);
*omega[2] = 0.0;


N3V_D (velocity,=,0.0,0.0,0.0);
N3V_D (omega,=,0.0,1.0,0.0);

return;
}

but i returns error message like below,
..\..\src\rotation_test_17.c(5) : error C2100: illegal indirection
..\..\src\rotation_test_17.c(6) : error C2100: illegal indirection
..\..\src\rotation_test_17.c(7) : error C2100: illegal indirection

Anyone who can help me modify the code or any comments?
(Please help me...)
It would be very help and thank you so much in advance.

Best regards,
Denis

[AlexanderZ]

omega is a scalar,
you have to define origin and axis

Ansys Fluent Customization manual -> DEFINE_ZONE_MOTION

best regards

[denis Kim]

Thank you for your valuable comments.

i am recoding in consideration of your comments.

can you give me a comments below UDF?

#include "udf.h"
DEFINE_ZONE_MOTION(rotation,omega,axis,origin,velo city,time,dtime)
{
*omega = 2*3.141592*0.125*0.872*cos(2*3.141592*0.125*time);

N3V_S(origin,=,0.0); /* default values, line could be omitted */
N3V_D(axis,=,0.0,1.0,0.0); /* default values, line could be omitted */

return;
}

Thank you in advance.

Best regards,

Kim

[AlexanderZ]

very good code,
try it

best regards

[denis Kim]

very thanks@@!

It works!!

Best wishes,

Denis

[movaffagh]

hi i have a problem with my code in mesh motion rotation.i have a fuel assembly and i should simulate heaving and rolling motions. my code its in below:

#include<udf.h>
#define period 6
#define angular_freq 2*M_PI*period
#define tetamax 10*M_PI/180
DEFINE_ZONE_MOTION(fmotion,omega,axis,origin,veloc ity,time,dtime)
{

*omega =tetamax*sin(angular_freq*time);

N3V_D (velocity,=,0.0,0.0,0.0);
N3V_S(origin,=,0.0);
N3V_D(axis,=,1.0,0.0,0.0);

return;
}

i need my geometry rotate between -10 and 10 degree but with this code my geo rotate between 0 and 10 degre
what's my problem?
thank's

[vinerm]

That's because the angular frequency is wrong. Divide it by 180.

[movaffagh]

Originally Posted by vinerm

That's because the angular frequency is wrong. Divide it by 180.

dear vinerm:why i should divide? i have pi in my angular frequency and its in radian unit. whats unit i should use?

[vinerm]

You are right. You don't really need that and it actually changes nothing except reducing the rotational speed. But if 6 is really the time period then your equation for angular frequency is wrong. It should be . And with that, you get one complete cycle within 6 seconds, including -0.1745 as minimum value, which corresponds to -10 in degree.

[movaffagh]

Originally Posted by vinerm

You are right. You don't really need that and it actually changes nothing except reducing the rotational speed. But if 6 is really the time period then your equation for angular frequency is wrong. It should be . And with that, you get one complete cycle within 6 seconds, including -0.1745 as minimum value, which corresponds to -10 in degree.

thank you for your help.