Zone position from UDF

montag dp · August 2, 2010, 10:32

All,

I'm attempting to simulate a flapping and pitching wing in Fluent using a dynamic mesh and define_cg_motion macro. I'm having some issues keeping the wing rotating only about the two desired axes. I'm using the Euler rotation rate equations to transform the desired rotations into cg (body) coordinates, and I think it would be helpful if I could get the instantaneous position and rotation of the zone while the macro is running. If I run it for a little bit and then go to Dynamic Mesh Zones Fluent displays these positions, so it seems like it should be possible to access them from the UDF. Can anyone tell me how to do this?

Thanks,
Dan

montag dp · August 2, 2010, 16:11

For those interested, I found out how to do it. I stumbled across it while doing a search on the forums. The current zone orientation can be returned with the DT_THETA(dt) macro. Just be careful because it seems to return the orientation in degrees, not radians, so you must convert it to use in trig expressions.

August 2, 2010, 10:32	Zone position from UDF	#1
montag dp Member Join Date: Jul 2010 Posts: 38 Rep Power: 15	All, I'm attempting to simulate a flapping and pitching wing in Fluent using a dynamic mesh and define_cg_motion macro. I'm having some issues keeping the wing rotating only about the two desired axes. I'm using the Euler rotation rate equations to transform the desired rotations into cg (body) coordinates, and I think it would be helpful if I could get the instantaneous position and rotation of the zone while the macro is running. If I run it for a little bit and then go to Dynamic Mesh Zones Fluent displays these positions, so it seems like it should be possible to access them from the UDF. Can anyone tell me how to do this? Thanks, Dan

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Problem in IMPORT of ICEM input file in FLUENT	csvirume	FLUENT	2	September 9, 2009 01:08
DPM UDF particle position using the macro P_POS(p)[i]	dm2747	FLUENT	0	April 17, 2009 01:29
Error to re-open fluent case file	J.Gimbun	FLUENT	0	April 27, 2006 08:42
UDF for orous zone porosity	ap	FLUENT	2	November 10, 2004 18:26
Sliding mesh error	Karl Kevala	FLUENT	4	February 21, 2001 15:52

August 2, 2010, 16:11		#2
montag dp Member Join Date: Jul 2010 Posts: 38 Rep Power: 15	For those interested, I found out how to do it. I stumbled across it while doing a search on the forums. The current zone orientation can be returned with the DT_THETA(dt) macro. Just be careful because it seems to return the orientation in degrees, not radians, so you must convert it to use in trig expressions.