Reply To: Tutorial or Help for 2 way FSI

[ashishkumar.gupta]

 

Hi Paul,

‘So what you’re saying is the balls do not rotate with the IR speed, but at a speed slightly different due to some slipping? ‘

– YES different SPEED without slipping

You guessed it right. We input Inner Race (1000 RPM) and Outer Race(fixed support) and Frictional contacts between Ball and Races make it rotate and translate ….this is in pure only Ansys Mechanical Simulation (NON-FSI)

Now, In 2 way FSI, we have very thin film of Fluid between Ball and Race , which leads to FrtictionLESS contact and FSI helps in the Transfer of Forces between Mechanical (Ball/Race) and Fluent (Fluid) to make Ball rotate and translate.

 

’This is not going to work with the domain you have currently, as the ball will move out of the domain and lose contact with the surrounding structure(!).'

— I Simulate it for very short time till they are all in contact with each other. I can calculate that time too. In addition, we can use Cyclic Symmetry and Periodic B.C….So its is a CLOSED  LOOP….

 

‘Is this ball motion pre-defined, or do you want to predict it?’

– Can be both.  it is constant angular velocity concept, so the RPM of all objects (IR, OR, Ball) can be calculated mathematically and if needed, can also be provided as Input [ But in pure Ansys Mechanical Simulation (NON-FSI), Ball movement is the OUTPUT]

 

‘If it’s pre-defined/constant, you could solve the whole problem in the reference frame of the ball, since IR and OR are surfaces of revolution.

Then you need to adjust wall boundary conditions accordingly.’

How can we do it? that is what I am confused now. Because I thought the FSI can make the ball rotate & translate but it was not able to.

If I want to give wall speed to Ball, I am unable to give both the Rotational Speed & Revolutional Speed.

Is there any other alternative to make it work?