A Novel Flow-induced Motion Energy Harvesting with Coupled Mechanism of Time-varying Stiffness and Passive Turbulence Control

TL;DR

This paper presents a biomimetic, flow-induced motion energy harvesting mechanism that combines passive turbulence control and time-varying stiffness to significantly improve efficiency and power output in ocean energy harvesting.

Contribution

It introduces a novel coupled mechanism integrating boundary layer modulation with dynamic stiffness adjustments for enhanced ocean energy harvesting.

Findings

Double energy harvesting efficiency with specific configurations.

Up to 57% increase in power output and vibration amplitude.

Reduced initial harvesting frequency.

Abstract

The ocean contains a substantial amount of energy, and the efficient harvesting of this energy holds significant importance. Drawing inspiration from the biomimicry of octopus tentacles, this study introduces a synergistic mechanism designed to optimize energy harvesting through flowinduced motions, integrating boundary layer modulation via passive turbulence control (PTC) with dynamic system stiffness adjustments via time-varying stiffness (SIN & Trapezoidal patterns). The implementation of PTC facilitates global stability by managing the local instabilities caused by variable stiffness, culminating in a highly effective energy harvesting capability. Our investigations summarize the requisite conditions for peak energy harvesting efficacy, notably within the SIN 80 degrees PTC and Trapezoid/60 degrees PTC arrangements, which have been demonstrated to double the efficiency of energy harvesting with up to 57%, alongside a reduction in initial harvesting frequency and an enhancement in both instantaneous power output and vibration amplitude. Furthermore, an energy transfer characteristic map has been compiled to illustrate the mechanism coupled between boundary layer modulation and time-varying stiffness. This research not only introduces novel perspectives but also stands as a significant stride in the realm of wide band and efficient energy harvesting in the ocean.