3D simulations of self-propelled, reconstructed jellyfish using vortex methods

TL;DR

This paper presents 3D vortex-based simulations of jellyfish propulsion, using real video data to model vortex dynamics and compare different swimming strokes, revealing how vortex formation influences speed.

Contribution

It introduces a novel 3D vortex particle simulation method with image-based geometry reconstruction for modeling jellyfish propulsion.

Findings

Stroke B produces higher velocity than Stroke A.

Jellyfish speed scales with the square root of Reynolds number.

Simulations visually demonstrate vortex ring formation and propulsion mechanisms.

Abstract

We present simulations of the vortex dynamics associated with the self-propelled motion of jellyfish. The geometry is obtained from image segmentation of video recordings from live jellyfish. The numerical simulations are performed using three-dimensional viscous, vortex particle methods with Brinkman penalization to impose the kinematics of the jellyfish motion. We study two types of strokes recorded in the experiment1. The first type (stroke A) produces two vortex rings during the stroke: one outside the bell during the power stroke and one inside the bell during the recovery stroke. The second type (stroke B) produces three vortex rings: one ring during the power stroke and two vortex rings during the recovery stroke. Both strokes propel the jellyfish, with stroke B producing the highest velocity. The speed of the jellyfish scales with the square root of the Reynolds number. The simulations are visualized in a fluid dynamics video.