Physics Student Research

Document Type

Article

Journal/Book Title/Conference

Physics of Fluids

Author ORCID Identifier

Ahmad Talaei https://orcid.org/0000-0003-4603-5666

Timothy J. Garrett https://orcid.org/0000-0001-9277-8773

Volume

37

Issue

6

Publisher

AIP Publishing LLC

Publication Date

6-9-2025

Journal Article Version

Accepted Manuscript

First Page

1

Last Page

12

Abstract

The accurate modeling of particle motion in viscous fluids at high Reynolds numbers remains a fundamental challenge, particularly under unsteady flow conditions where nonlinear effects dominate. This study introduces a revised unsteady drag formulation, extending its applicability beyond previous studies. By integrating classical solutions of the Navier–Stokes equations, the new formulation overcomes the limitations of the Maxey–Riley–Gatignol (MRG) equation, addressing non-physical memory effects associated with Basset drag and extending its applicability to higher Reynolds numbers.

Through experimental comparisons and direct numerical simulations (DNS), the revised equation of motion is compared to the MRG equation, both during steady-state conditions and non-equilibrium transitions. The revised formulation exhibits consistency with observations across a board range of Reynolds numbers. Furthermore, the DNS of particle-laden turbulence reveals enhanced clustering and collision–coalescence dynamics when using the revised drag force, emphasizing the formulation's capability to capture particle interactions in turbulent flows.

These findings provide critical insights into atmospheric and hydrodynamic applications, advancing our understanding of droplets settling, clustering, and growth in turbulent environments. The proposed framework holds potential for improving predictions in climate models, sediment transport, and other fields reliant on accurate particle dynamics.

Comments

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Ahmad Talaei, Timothy J. Garrett; Revised unsteady drag force and its impact on particle dynamics at high Reynolds numbers. Physics of Fluids 1 June 2025; 37 (6): 067121. https://doi.org/10.1063/5.0264261 and may be found at https://doi.org/10.1063/5.0264261 .

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