Research on Claw Motion Characteristics and Cavitation Bubbles of Snapping Shrimp.

Yuliang Yang,Jianxin Zhao,Shimu Qin,Dalin Wu,Changchun Di,Junqi Qin

doi:10.1155/2020/6585729

Abstract

Snapping shrimp produces a high-speed jet through the rapid closure of the snapper claw, which stimulates the formation of cavitation bubbles of various shapes. In order to explore the fast motion characteristics of snapper claw, the formation and change process of cavitation, and the physical principles underlying the biological phenomena, the equivalent model of snapper claw was constructed through CT scanning technology. A high-speed camera was used to capture the claw's motion characteristics, thereby simulating the production of cavitation bubbles by snapping shrimp. The results show that the rotation speeds of different species of snapping shrimps are different, as well as their motion characteristics. Cavitation is formed by the interaction of the pressure drop caused by the vortex at the nozzle with the inertia of the liquid inside the socket. Under the influence of the jet, the shapes of bubbles change from ring to cone, and eventually collapse into bubble clouds.

Highlights

Snapping shrimp is a member of the Alpheidae family
In order to elucidate the biophysical characteristics of these small shrimps, this paper studied the structure of snapper claw through CT scanning and established a 3D model of snapper claw, which was used to simulate the formation of cavitation bubbles
In response to the stimulation, the snapping shrimp tilted its dactyl to the maximum angle and stayed in that position for about a second, the dactyl moved to close the claw at an extreme rapid velocity around the joint

Summary

Introduction

Snapping shrimp is a member of the Alpheidae family It has asymmetrical claws, the larger of which can grow to about half its body size [1]. The snapping shrimp rapidly closes the larger claw [3], draining the water into the socket and forming a high-speed water jet of 32 m/s [4]. Because the high-speed water jet injection causes cavitation due to the strong pressure reduction effect of water and the rupture of the cavitation bubbles in front of the claw, the snapping shrimp generates a loud cracking noise of up to 210 dB at the source [6]. When the claw is closed [7], there is an angular offset between the dactyl and the propus, which prevents physical contact between these parts, indicating that the noise is caused by the bubble collapse

Methods

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Discussion

Conclusion