Dynamic Behaviors of Supersonic Granular Media under Vertical Vibration

TL;DR

This paper experimentally investigates the dynamic behaviors of supersonic granular media under vertical vibration, revealing shock wave propagation and temperature peaks during vibration cycles.

Contribution

It provides detailed experimental observations of shock phenomena and granular temperature distribution in vibrofluidized granular materials, highlighting supersonic effects.

Findings

Shock waves propagate in granular media with Mach number > 1.

Granular temperature peaks during compression and propagates upward.

Steepened fronts in temperature distribution indicate shock formation.

Abstract

We present experimental study of vibrofluidized granular materials by high speed photography. Statistical results present the averaged dynamic behaviors of granular materials in one cycle, including the variations of height, velocity and mechanical energy of the center of mass. Furthermore, time-space distribution of granular temperature which corresponds to the random kinetic energy shows that a temperature peak forms in the compression period and propagates upward with a steepened front. The Mach number in the steepened front is found to be greater than unity, indicating a shock propagating in the supersonic granular media.