I have a UDF that defines a sinusoidal mesh motion. The UDF looks like this:
#include "udf.h"
real oscillation(real angl_vel, real time)
{
real omega,amp;
omega=50.0;
amp=5.0*3.1415/180.0;
angl_vel=amp*omega*cos(omega*time);
return angl_vel;
}
I interpret this UDF in Fluent and there are no errors. I expect the mesh to rotate sinusoidally but it ends up making complete rotations, seemingly at a constant angular velocity. I am not sure why this behavior is seen. It would be great if someone familiar with using UDFs in Fluent could help.
Please let me know if any additional information is needed. Any help would be greatly appreciated. Thank You.
I have two question:
1) which programming language do you use? C or C++?
2) Do you make sure that your user defined function completely is defined through Define -> User defined -> Function -> Compile?
Let me know in advance.
Best.
1) I use a 'C' to program.
2) I don't compile it. I do the following:
Define -> User Defined -> Function -> Interpreted
When I try compiling, I have an issue while 'loading' (after 'building') hence I chose to interpret.
Thanks for your reply.
Dear Anand,
you defined a time, but you didn't get the correct time from the solver. Hence your time is zero and with cos (0) = 1 your velocity is constant.
You would have to write CURRENT_TIME in your time variable: time = CURRENT_TIME. For further information and examples, please check this ressource:
https://www.sharcnet.ca/Software/Fluent6/html/udf/node105.htm
Best regards,
Julian
Dear Mr. Julian Vogel,
Thank you very much for your input. I made the fix that you suggested and it works!
Thanks once again,
Regards,
Anand
Can I get an UDF of oscillating wall for creating of waves? Would be thankful for any help. stuck on the problem since a long time.
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