En
期刊文章
文章精选
当期目录
过刊浏览
高被引
高下载
特邀文章
专刊合集
待刊文章
Volume 110
您当前的位置：首页 > 期刊文章 > 过刊浏览 > Volumes 108-119 (2025) > Volume 110
Saraei, S. H., & Peters, B. (2026). Challenging the physical origin of tumbling in idealized settling of two spherical particles. Particuology, 110, 131-143. https://doi.org/10.1016/j.partic.2026.01.006
Challenging the physical origin of tumbling in idealized settling of two spherical particles
Sina Hassanzadeh Saraei *, Bernhard Peters
a Department of Engineering, University of Luxembourg, Luxembourg
b Faculty of Civil Engineering, Vilnius Gediminas Technical University, Lithuania
10.1016/j.partic.2026.01.006
Volume 110, March 2026, Pages 131-143
Received 24 October 2025, Revised 27 November 2025, Accepted 5 January 2026, Available online 20 January 2026, Version of Record 29 January 2026.
E-mail: sina.hassanzadeh@uni.lu; Bernhard.Peters@uni.lu; bernhard-josef.peters@vilniustech.lt
Highlights

• Applying a fully resolved CFD-DEM model to consider interaction between fluid and particles.

• Determining key parameters affecting the tumbling of spherical particles.

• Concluding that symmetrical falling of spherical particles could not initiate tumbling.

• Discovering that tumbling in case without initial geometrical offset is a numerical issue rather than a physical phenomenon.


Abstract

The drafting, kissing, and tumbling (DKT) behavior of falling spherical particles is widely used to validate CFD–DEM models. Although many studies report tumbling in idealized systems with spherical particles, the physical origin of this motion remains unclear, especially when the density difference between the particles and the fluid is small. In this work, we revisit the classic DKT configuration using a fully resolved CFD–DEM model based on the immersed boundary method. Our analysis systematically examines whether the observed tumbling is a genuine physical phenomenon or a numerical artifact. Our results indicate that, in the absence of real world imperfections such as surface roughness or shape irregularities, tumbling is primarily caused by numerical errors rather than inherent flow instabilities. This finding challenges the conventional interpretation of DKT as a purely physical benchmark and highlights the need for caution when using tumbling to validate CFD–DEM models. By distinguishing numerical artifacts from physical effects, this study provides new guidance for model validation and has important implications for extending CFD–DEM to dense particle systems.

Graphical abstract
Keywords
Computational fluid dynamics; Discrete element method; Immersed boundary method; Tumbling
文章导读