How to make Rotating Ball?

Benjamin Lee · November 12, 2019, 06:15

Hi, I'm really really new student who is recently learning fluent in south korea.

I wanna simulate the 3D rotating ball in fluent.

In class I always learned only static golf ball. I mean the ball doesn't rotate.

But I want to rotate the ball while the program calculating.

Would you please help me how to do that? or give me some practical link.

Thank you very much.

LuckyTran · November 12, 2019, 11:29

You can jut use a moving wall by giving the wall a velocity. Normally the walls do not move (with a velocity of 0 m/s), but you can apply any number. Everything else is the same as a static ball.

jbo214 · November 12, 2019, 11:41

There are several possible approaches.

Change the wall motion from stationary to moving and specify a rotational velocity.
Use the dynamic mesh feature/6 DOF solver and specify an initial rotational velocity. The solver will then calculate the ball's position and velocities for every time step.
Use an overset meshing technique and specify a rotational velocity to the zone containing the golf ball wall surface.
Use an overset meshing technique in combo with the 6 DOF solver. This way, no remeshing needs to happen.

Benjamin Lee · November 12, 2019, 23:58

Quote:

Originally Posted by jbo214

There are several possible approaches.

Change the wall motion from stationary to moving and specify a rotational velocity.
Use the dynamic mesh feature/6 DOF solver and specify an initial rotational velocity. The solver will then calculate the ball's position and velocities for every time step.
Use an overset meshing technique and specify a rotational velocity to the zone containing the golf ball wall surface.
Use an overset meshing technique in combo with the 6 DOF solver. This way, no remeshing needs to happen.

Thank you for reply! and I understood some extent.

I have one more question. I made a ball and enclosure and then used boolean to subtract and finally i made it as 1 body

For apply case 1, Do I have to make a ball and fluid way for 2 body??

Sorry for my poor explanation. Thank you.

jbo214 · November 13, 2019, 00:06

I don't really understand your question, but if you have a single conformally meshed domain, you can change the wall motion settings for the ball. See the attached pic (note its from a 2D setup, not 3D).

Determine the center of rotation, specify the axis of rotation, and a rotational velocity.

wallbc.PNG

LuckyTran · November 13, 2019, 11:45

You don't mesh the ball. There's no flow inside the ball, you are doing CFD. You only mesh the ball if you want to model other stuff happening in the ball. All you need is the spherical wall surface which contains all the interaction between the flow and the ball. I.e. draw a control volume for just the fluid.

November 12, 2019, 06:15	How to make Rotating Ball?	#1
Benjamin Lee New Member WooHyeong Lee Join Date: Nov 2019 Posts: 3 Rep Power: 6	Hi, I'm really really new student who is recently learning fluent in south korea. I wanna simulate the 3D rotating ball in fluent. In class I always learned only static golf ball. I mean the ball doesn't rotate. But I want to rotate the ball while the program calculating. Would you please help me how to do that? or give me some practical link. Thank you very much.

November 12, 2019, 11:29		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,675 Rep Power: 66	You can jut use a moving wall by giving the wall a velocity. Normally the walls do not move (with a velocity of 0 m/s), but you can apply any number. Everything else is the same as a static ball. Benjamin Lee likes this.

November 12, 2019, 11:41		#3
jbo214 Member Joshua Join Date: Aug 2014 Posts: 49 Rep Power: 11	There are several possible approaches. Change the wall motion from stationary to moving and specify a rotational velocity. Use the dynamic mesh feature/6 DOF solver and specify an initial rotational velocity. The solver will then calculate the ball's position and velocities for every time step. Use an overset meshing technique and specify a rotational velocity to the zone containing the golf ball wall surface. Use an overset meshing technique in combo with the 6 DOF solver. This way, no remeshing needs to happen. Benjamin Lee likes this.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
[openSmoke] libOpenSMOKE	Tobi	OpenFOAM Community Contributions	562	January 25, 2023 09:21
Quick question - Can I use rotating wall for a spinning rugby ball (with seams)??	Rake32	FLUENT	5	March 1, 2017 14:24
Running UDF with Supercomputer	roi247	FLUENT	4	October 15, 2015 13:41
rotating ball in water	Aliz	Main CFD Forum	0	February 21, 2011 03:43
Simulates the rotating ball	nvtrieu	Siemens	3	July 6, 2009 15:12

November 13, 2019, 00:06		#5
jbo214 Member Joshua Join Date: Aug 2014 Posts: 49 Rep Power: 11	I don't really understand your question, but if you have a single conformally meshed domain, you can change the wall motion settings for the ball. See the attached pic (note its from a 2D setup, not 3D). Determine the center of rotation, specify the axis of rotation, and a rotational velocity. wallbc.PNG

November 13, 2019, 11:45		#6
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,675 Rep Power: 66	You don't mesh the ball. There's no flow inside the ball, you are doing CFD. You only mesh the ball if you want to model other stuff happening in the ball. All you need is the spherical wall surface which contains all the interaction between the flow and the ball. I.e. draw a control volume for just the fluid.