2021/06/17 by Melody X. Lim, Bryan VanSaders, Lim, Melody X. +5 · 1 citation
Biochemistry, Genetics and Molecular Biology · Engineering · #FOS: Physical sciences #Granular flow and fluidized beds #Magnetic and Electromagnetic Effects #Microfluidic and Bio-sensing Technologies #Soft Condensed Matter (cond-mat.soft)
paper · pdf · doi:10.48550/arxiv.2106.09765
openalex publication_date 2021/06/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We investigate a model system for the rotational dynamics of inertial many-particle clustering, in which sub-millimeter objects are acoustically levitated in air. Driven by scattered sound, levitated grains self-assemble into a monolayer of particles, forming mesoscopic granular rafts with both an acoustic binding energy and a bending rigidity. Detuning the acoustic trap can give rise to stochastic forces and torques that impart angular momentum to levitated objects. As the angular momentum of a quasi-two-dimensional granular raft is increased, the raft deforms from a disk to an ellipse, eventually pinching off into multiple separate rafts, in a mechanism that resembles the break-up of a liquid drop. We extract the raft effective surface tension and elastic modulus, and show that non-pairwise acoustic forces give rise to effective elastic moduli that scale with the raft size. We also show that the raft size controls the microstructural basis of plastic deformation, resulting in a transition from fracture to ductile failure.