Impact of Softness of Particles on Rheology of Dilute Granular Gases

TL;DR

This study explores how particle softness influences the flow behavior of dilute granular gases, revealing deviations from classical scaling laws and identifying limits of existing kinetic theory at high shear rates.

Contribution

It combines numerical simulations and theoretical analysis to examine the impact of particle softness on granular gas rheology, highlighting the theory's applicability and limitations.

Findings

Kinetic theory predicts deviations from Bagnold scaling at low shear rates.

Simulation results agree with theory below a certain shear rate.

No theoretical solutions exist above this shear rate due to energy imbalance.

Abstract

We numerically and theoretically investigate how the softness of particles affects the rheology of sheared dilute granular gases. We find that the kinetic theory predicts the deviation of the flow curve from the Bagnold scaling, and it works well below a certain shear rate when we compare with the simulation results. It is also found that there is no theoretical solution above this shear rate, which is because the energy loss due to inelastic collisions cannot be balanced with the energy injection by the shear.