Workshop on Numerical Methods and Analysis in CFD - Abstract

Richter, Thomas

Fluid-rigid body interactions with large motion and contact

We consider a simple problem: a solid, e.g. a sphere, is falling towards the bottom in a container filled with a liquid.

First, we present efficient simulation methods that cope with this large-displacement problem. The fundamental problem is that the solid is moving substantially and therefore the flow domain undergoes strong changes.

Then we deal with the contact of the solid with the bottom of the container. Analytically this problem is already well studied and here the unpleasant result is that contact in finite time is not possible if the fluid will be assumed to be incompressible. In reality, however, we will find that the ball bounces off the ground and comes to rest only after a few contacts.

This situation is difficult to grasp numerically. Contact implies a topology change of the domain. We introduce different modeling and discretization approaches and present numerical benchmarks, which are also backed by experimental data.