# Which ANSYS Analysis Systems to use, Rigid Dynamics or Fluent, please?

Member Posts: 2

I am new to Ansys and would like to be able to solve a particular problem. I'd like to create a model to study a ping pong ball flighting in the air. I want to test when a ping pong ball is shot into air with different velocities and spins, how the windy directions and velocities affect the ball velocity, spin and trajectory.

I have started to use Fluent and doubtit is the right package to use. I would appreciate if someone could tell me what Ansys Analysis Tool should be used and what the main steps to tackle the ping-pong ball problem are within Ansys. Thank you!

Tagged:

• UKPosts: 12,230Forum Coordinator
edited April 2021

Fluent, you're wanting to solve the air flow around the ball. Note modelling sphere's is very hard due to the flow shedding. Read up on the work by John Hart at Sheffield Hallam University and Bert Blocken at  Eindhoven University of Technology. Tom Allen at Manchester is also involved in sports simulations, but not sure if he does much CFD.

• Posts: 4Member

Tom Allen is one of my colleagues and he sends me here. I will look at John and Bert's work - thank you!

In the Geometry, I simply dragged and placed a Sphere object and changed the "Solid" text to "Hollow". Has this changed the sphere to a hollpw ball?

Otherwise, I've read so much on how to create a hollow ball and it seems so hard to create one. By the way, I am using Ansys 2020 R2.

Is there any way I could not use Fluent but physics of rigid objects?

• Posts: 4Member

Hi Rob again, I am not particularly interested in the air flow around the ball but interested in how the air flow affects the ball speeds and spins. With air being still, I am interested in how spins affect the ball's trajectory.

• UKPosts: 12,230Forum Coordinator

The motion is entirely a function of the initial force imparted to the ball, gravity and drag. Drag being rather important, which is why you need the CFD solver. We can model the motion in Fluent, read up on the 6DOF solver. Tom can help you with the UDFs that will be required.