Wall motion as a UDF, is it possible?

linch · August 28, 2009, 09:14

Hi everyone,

first of all I would like to describe shortly the problem I am working at.

I struggle to model a belt motion in Fluent. I hope everyone of you can imagine a belt moving along his path through some kind of fluid. I am interested in computing the heat transfer within the belt an try to work out two alternative models:

a) the belt as a solid
b) the belt as a wall with the shell conduction model activated

to a) :
I can move the mesh within the band by activating "Dynamic Mesh" with "layering" and using the DEFINE_GRID_MOTION macro to move the grid of the solid manually along the defined path. The problem is that the surrounding fluid doesn't follow the solid. For an even problem I can cope with this problem by activating the "moving wall" option for the wall adjacent to the fluid zone. For a complex case though, the wall velocity hast to be normal to the belt path. Though the velocity magnitude is constant, but the direction is different for each cell. Any Idea how can I realize this? I don't know if there is any possibility to attach an UDF to the wall motion.

linch · August 31, 2009, 10:18

No ideas? Or didn't I express myself clearly?

Please tell me, if my description was incomprehensible.

August 28, 2009, 09:14	Wall motion as a UDF, is it possible?	#1
linch Senior Member Illya Shevchuk Join Date: Aug 2009 Location: Darmstadt, Germany Posts: 176 Rep Power: 17	Hi everyone, first of all I would like to describe shortly the problem I am working at. I struggle to model a belt motion in Fluent. I hope everyone of you can imagine a belt moving along his path through some kind of fluid. I am interested in computing the heat transfer within the belt an try to work out two alternative models: a) the belt as a solid b) the belt as a wall with the shell conduction model activated to a) : I can move the mesh within the band by activating "Dynamic Mesh" with "layering" and using the DEFINE_GRID_MOTION macro to move the grid of the solid manually along the defined path. The problem is that the surrounding fluid doesn't follow the solid. For an even problem I can cope with this problem by activating the "moving wall" option for the wall adjacent to the fluid zone. For a complex case though, the wall velocity hast to be normal to the belt path. Though the velocity magnitude is constant, but the direction is different for each cell. Any Idea how can I realize this? I don't know if there is any possibility to attach an UDF to the wall motion.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Accessing wall shear stress using UDF	Robert	Fluent UDF and Scheme Programming	2	July 31, 2013 09:34
fluent probelm"mesh motion udf"	bestrcsekhar	Main CFD Forum	0	November 2, 2008 02:38
UDF hook on the WALL boundary condition	Luke	FLUENT	0	June 7, 2006 12:54
UDF error CG Motion	Alex	FLUENT	0	March 22, 2006 18:40
Vibrating / Deforming Wall UDF	Qureshi	FLUENT	2	January 16, 2004 05:48

August 31, 2009, 10:18		#2
linch Senior Member Illya Shevchuk Join Date: Aug 2009 Location: Darmstadt, Germany Posts: 176 Rep Power: 17	No ideas? Or didn't I express myself clearly? Please tell me, if my description was incomprehensible.