Settling dynamics of an oloid: experiments and simulations

Fuente: arXiv
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Main Authors: Flapper, Mees M., Piumini, Giulia, Verzicco, Roberto, Huisman, Sander G., Lohse, Detlef
Format: Preprint
Published: 2025
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author Flapper, Mees M.
Piumini, Giulia
Verzicco, Roberto
Huisman, Sander G.
Lohse, Detlef
author_facet Flapper, Mees M.
Piumini, Giulia
Verzicco, Roberto
Huisman, Sander G.
Lohse, Detlef
contents This study presents a combined experimental and computational investigation of an oloid shaped particle settling in a quiescent fluid. The oloid, a unique convex shape with anisotropic geometry, provides a distinctive model for exploring how a particle's shape and orientation affect its settling dynamics. The settling oloids are tracked experimentally for Galileo numbers $48 \leq \text{Ga} \leq 5.4 \cdot 10^3$, using two particle sizes ($D_{\text{eq}}$ = 21.6 mm, and $D_{\text{eq}}$ = 10.8 mm). The density ratio between the particle and fluid $Γ$ = $\frac{ρ_p}{ρ_f}$ ranges from $1.11 \leq Γ\leq 1.30$ in the experiments. Computationally, the Galileo numbers $10 \leq \text{Ga} \leq 100$ are simulated, with $Γ= 2$. The experimental findings and numerical results are in good agreement, and give a consistent idea of the oloid settling dynamics. Our results indicate two distinct falling modes for the oloid, separated by Galileo number. The stable mode is characterised by a preferential orientation, with a rotation around the vertical axis, whereas the tumbling mode has randomly distributed orientation and rotation statistics. We characterise the falling velocity, orientation, and rotation dynamics of the oloids over a range of Galileo numbers. Additionally, the influence of the initial orientation is revealed to determine the rotation dynamics at low Galileo numbers.
format Preprint
id arxiv_https___arxiv_org_abs_2511_05137
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Settling dynamics of an oloid: experiments and simulations
Flapper, Mees M.
Piumini, Giulia
Verzicco, Roberto
Huisman, Sander G.
Lohse, Detlef
Fluid Dynamics
This study presents a combined experimental and computational investigation of an oloid shaped particle settling in a quiescent fluid. The oloid, a unique convex shape with anisotropic geometry, provides a distinctive model for exploring how a particle's shape and orientation affect its settling dynamics. The settling oloids are tracked experimentally for Galileo numbers $48 \leq \text{Ga} \leq 5.4 \cdot 10^3$, using two particle sizes ($D_{\text{eq}}$ = 21.6 mm, and $D_{\text{eq}}$ = 10.8 mm). The density ratio between the particle and fluid $Γ$ = $\frac{ρ_p}{ρ_f}$ ranges from $1.11 \leq Γ\leq 1.30$ in the experiments. Computationally, the Galileo numbers $10 \leq \text{Ga} \leq 100$ are simulated, with $Γ= 2$. The experimental findings and numerical results are in good agreement, and give a consistent idea of the oloid settling dynamics. Our results indicate two distinct falling modes for the oloid, separated by Galileo number. The stable mode is characterised by a preferential orientation, with a rotation around the vertical axis, whereas the tumbling mode has randomly distributed orientation and rotation statistics. We characterise the falling velocity, orientation, and rotation dynamics of the oloids over a range of Galileo numbers. Additionally, the influence of the initial orientation is revealed to determine the rotation dynamics at low Galileo numbers.
title Settling dynamics of an oloid: experiments and simulations
topic Fluid Dynamics
url https://arxiv.org/abs/2511.05137