Numerical investigation of the flow inside a precession-driven cylindrical cavity with additional baffles using an immersed boundary method

Abstract

In this paper, we present a numerical approach to solve the Navier–Stokes equations for arbitrary vessel geometries by combining a Fourier-spectral method with a direct-forcing immersed boundary method, which one allows to consider solid–fluid interactions. The approach is applied to a paradigmatic setup motivated by the precession dynamo experiment currently under construction at Helmholtz–Zentrum Dresden–Rossendorf. The experiment consists of a fluid-filled cylinder rotating about two axes, which induces a precession-driven flow inside the cavity. The cylinder is also equipped with baffles at the end caps with adjustable penetration depth to impact the flow. The numerical details and simulation results for the spin-up and precession-driven flow in a circular cylinder with additional baffles are presented. The results provide a first confirmation that the use of such baffles in the precession dynamo experiment is a useful way of influencing the flow, allowing more efficient driving without changing the known flow structure too much.