Effects of particle shape and density ratio on energy dissipation pathways in drafting, kissing and tumbling--颗粒学报PARTICUOLOGY

Ugwuodo, U. M., Li, X., Wang, C., & Liu, G. (2026). Effects of particle shape and density ratio on energy dissipation pathways in drafting, kissing and tumbling. Particuology, 114, 320-336. https://doi.org/10.1016/j.partic.2026.04.020

Effects of particle shape and density ratio on energy dissipation pathways in drafting, kissing and tumbling

Ugochukwu Marcellus Ugwuodo, Xiaohui Li, Chunlei Wang, Guodong Liu^*

School of Energy Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China

10.1016/j.partic.2026.04.020

Volume 114, July 2026, Pages 320-336

Received 24 February 2026, Revised 13 April 2026, Accepted 23 April 2026, Available online 6 May 2026, Version of Record 14 May 2026.

E-mail: gdliu@hit.edu.cn

Highlights

• Coupled LBM–DEM PR-DNS was used to study DKT of settling volume-equivalent ellipsoidal particle pairs.

• Particle sphericity modulates post-contact relaxation, with elongated particles showing staged angular-momentum decay and faster vorticity collapse.

• Near-spherical particles retain higher kinetic energy and sustain fluid disturbance for longer durations.

• Increasing particle–fluid density ratio delays response peaks and shifts kinetic-energy redistribution to later DKT stages.

Abstract

The Drafting, Kissing, and Tumbling (DKT) process reveals key features of particle–fluid–particle interactions in suspensions, but how particle shape and density regulate energy dissipation remains unclear. Using a coupled LBM-DEM-based Particle Resolved-Direct Numerical Simulation (PR-DNS) framework, we quantify the roles of sphericity (0.5–1.0) and particle–fluid density ratio (2–20) on dissipation pathways and rates of two interacting volume-equivalent ellipsoids. We show that shape modulates dissipation modes: elongated particles (sphericity ≈ 0.5–0.8) undergo staged angular momentum relaxation and abrupt vorticity decay, whereas near-spherical ones (sphericity ≈ 0.9–1.0) maintain higher kinetic energy and slower vorticity decay, consistent with persistent compact wakes. Density ratio modulates dynamics: low density ratio (2–5) enhances angular momentum equalization and accelerates vorticity decay, while high density ratio (10–20) delays response and prolongs vorticity plateaus. Sphericity and density ratio shift kinetic energy dominance during DKT, with near-spherical particles favoring stronger post-tumbling rotational energy, while increasing density ratio delays and redistributes energy toward later interaction stages. These results establish that elongated particles accelerate flow stabilization via rapid vorticity collapse, while spherical shapes and high density ratios prolong agitation. The findings provide predictive guidelines for tailoring dissipation in dense and dilute particulate systems.

Graphical abstract

Keywords

Drafting kissing and tumbling; Particle sphericity; Particle–fluid density ratio; Energy dissipation; Direct numerical simulation

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