# Numerical benchmarking of fluid-rigid body interactions

## TL;DR

This paper introduces a benchmark problem for fluid-rigid body interactions involving a fixed-center spherical obstacle, providing a standard for evaluating numerical methods in both 2D and 3D settings.

## Contribution

It presents a novel benchmark problem for fluid-rigid body interactions, including detailed problem definitions and reference solutions for method comparison.

## Key findings

- Multiple numerical approaches are summarized and compared.
- Reference intervals for key quantities are provided.
- The benchmark facilitates standardized evaluation of fluid-structure interaction methods.

## Abstract

We propose a fluid-rigid body interaction benchmark problem, consisting of a solid spherical obstacle in a Newtonian fluid, whose centre of mass is fixed but is free to rotate. A number of different problems are defined for both two and three spatial dimensions. The geometry is chosen specifically, such that the fluid-solid partition does not change over time and classical fluid solvers are able to solve the fluid-structure interaction problem. We summarise the different approaches used to handle the fluid-solid coupling and numerical methods used to solve the arising problems. The results obtained by the described methods are presented and we give reference intervals for the relevant quantities of interest.