Reply To: Tutorial or Help for 2 way FSI

[Paul Hutcheson]

Of course Mechanical can drive fluid motion, this is what system coupling is used for.

So if your fluid is oil, what is the lubricant? If is just the oil film in between, then you don't have mechanical contact. Neither in reality nor in the simulation. Frictionless support is ok in this case, to prevent fluid mesh collapse by using an offset as discussed previously.

I have given you all the details required now to setup this FSI case.

Here remember we have set a wall velocity on the IR in Fluent. This will create flow, you could say the lubricant flow. This flow will create a shear stress on the ball FSI interface. This shear stress will create a torque on the ball and cause it to rotate. I recommend constraining the ball to rotate only about its rotation axis (z). Either a revolute joint (ground to mobile) or a remote displacement with only rot Z free. Then the ball can only rotate!

If the ball is not rotating, you need to measure the torque as I said and work out its expected motion.