The effect of finite container size on granular jet formation

Abstract

When an object is dropped into a bed of fine, loosely packed sand, a surprisingly energetic jet shoots out of the bed. In this work we study the effect that boundaries have on the granular jet formation. We did this by (i) decreasing the depth of the sand bed and (ii) reducing the container diameter to only a few ball diameters. These confinements change the behavior of the ball inside the bed, the void collapse, and the resulting jet height and shape. We map the parameter space of impact with Froude number, ambient pressure, and container dimensions as parameters. From these results we propose a new explanation for the thick-thin structure of the jet reported by several groups [J.R.Royer \textit{et al}., Nature Phys. \textbf{1}, 164 (2005)], [G.Caballero \textit{et al}., Phys. Rev. Lett. \textbf{99}, 018001 (2007)] and [J.O. Marston, \textit{et al}., Physics of Fluids \textbf{20}, 023301 (2008)].

15 pages, 19 figures

References in corpus (6)

• Unified force law for granular impact cratering
• Low-speed impact craters in loose granular media
• Controlled impact of a disk on a water surface: Cavity dynamics
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Cited by in corpus (6)

• Drag force scaling for penetration into granular media
• The role of interstitial gas in determining the impact response of granular beds
• Length and time scales of a liquid drop impact and penetration into a granular layer
• High-speed X-ray imaging of a ball impacting on loose sand
• Impact drag force exerting on a projectile penetrating into a hierarchical granular bed
• Giant drag reduction due to interstitial air in sand