Discontinuous shear thickening of a moderately dense inertial suspension of hydrodynamically interacting frictionless soft particles

¹ Department of Mechanical Systems Engineering and Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
² Department of Industrial Technology and Innovation, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184–8588, Japan
³ Yukawa Institute for Theoretical Physics, Kyoto University, Kitashirakawa Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan

^* e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
^** Present address: Suzuki Motor Corporation, 300 Takatsukacho, Minami-ku, Hamamatsu, Shizuoka 432-8611, Japan
^*** e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Published online: 1 December 2025

Abstract

We demonstrate that discontinuous shear thickening (DST) can occur even in moderately dense, inertial suspensions of hydrodynamically interacting, frictionless soft particles. Using the Lubrication-Friction Discrete Element Method, our simulations reveal that DST can emerge at lower particle densities, provided that both the inertia of the suspended particles and their softness are sufficiently pronounced. Furthermore, we show that, under these conditions, the DST behavior obtained from the simulation qualitatively agrees with that predicted by kinetic theory, even without accounting for hydrodynamic interactions. These findings expand the understanding of DST in soft particle systems and highlight the importance of particle inertia and softness in controlling rheological behavior.