HELP . . . Vertical motion of a wing

Phil_QM · July 27, 2011, 11:57

I am trying to model vertical movement of an airfoil.

I currently have a mesh which works well for normal flows over it but I am trying to look at the effects of vertical oscillations on the forces of the airfoil.

My problem is that I cannot work out how to get my airfoil to translate.

Thanks
Phil

AdrienL · July 29, 2011, 06:15

Hey,

to translate your mesh you have to use a dynamic mesh (DEFINE_CG_MOTION).
You can find some stuff about it in the UDF manual.

If you have any questions ...

bye

Phil_QM · August 26, 2011, 07:45

Hi again, I have had to take some time away from this project but now have some more time to spend on it, I have managed to write a udf though seem to have some issues with it.
I get the following warning come up when I apply my UDF to my airfoil.
"Warning: incorrect cg motion UDF FOILMOTION on zone 7 (assuming no motion)"

The UDF I am using is bellow
#include <udf.h>
DEFINE_CG_MOTION(FOILMOTION, DT, VEL, OMEGA, TIME, DTIME)
{
VEL[1]=sin(CURRENT_TIME)
}

Do you have any idea what could be wrong?
Thanks

July 27, 2011, 11:57	HELP . . . Vertical motion of a wing	#1
Phil_QM New Member Join Date: Jul 2011 Location: London, UK Posts: 6 Rep Power: 15	I am trying to model vertical movement of an airfoil. I currently have a mesh which works well for normal flows over it but I am trying to look at the effects of vertical oscillations on the forces of the airfoil. My problem is that I cannot work out how to get my airfoil to translate. Thanks Phil

July 29, 2011, 06:15		#2
AdrienL Member Adrien Lemoine Join Date: Jun 2011 Location: Paris,France Posts: 31 Rep Power: 15	Hey, to translate your mesh you have to use a dynamic mesh (DEFINE_CG_MOTION). You can find some stuff about it in the UDF manual. If you have any questions ... bye __________________ ------------------------------------------- Plz add reputation if the answer is correct A cœur vaillant rien d'impossible ------------------------------------------

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August 26, 2011, 07:45		#3
Phil_QM New Member Join Date: Jul 2011 Location: London, UK Posts: 6 Rep Power: 15	Hi again, I have had to take some time away from this project but now have some more time to spend on it, I have managed to write a udf though seem to have some issues with it. I get the following warning come up when I apply my UDF to my airfoil. "Warning: incorrect cg motion UDF FOILMOTION on zone 7 (assuming no motion)" The UDF I am using is bellow #include <udf.h> DEFINE_CG_MOTION(FOILMOTION, DT, VEL, OMEGA, TIME, DTIME) { VEL[1]=sin(CURRENT_TIME) } Do you have any idea what could be wrong? Thanks