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Accueil > Actualités > Séminaires > Séminaires 2022

Mardi 15 Mars 11h00 - LEGI Salle K118

Markus Uhlmann, KIT

Title : Settling of many spheroids at Reynolds numbers of O(100)

Contact : Nathanael Machicoane

Abstract : When an ensemble of heavy particles settles in an ambient fluid, wake-induced clustering in columnar structures may occur, leading to much enhanced average settling velocities. This phenomenon has been thoroughly studied for spherical rigid particles [1]. Less data is available for particles whose shape deviates from a sphere. Here we are going to consider oblate spheroids with an aspect ratio relatively close to unity, focusing on the dilute regime. We describe an extension of the immersed boundary method for non-spherical particles and discuss high-fidelity benchmarks [2]. Our results show that the collective dynamics of oblate spheroids are quite different from those of spheres. In particular, strong clustering is observed over a range of Galileo numbers, irrespective of the regime of motion of an equivalent isolated particle. We will discuss these results in the light of an analysis of "drafting-kissing-tumbling" of pairs of spheroids.

[1] M. Uhlmann and T. Doychev. J. Fluid Mech., 752:310-348, 2014.
[2] M. Moriche, M. Uhlmann, and J. Dusek. Int. J. Multiphase Flow, 1346:103519, 2021.