Toward a high performance and strong resilience wind energy harvester assembly utilizing flow-induced vibration: Role of hysteresis

Wind energy harvester utilizing flow-induced vibration (FIV-WEH) has attracted much attention because of its ability to capture low-speed wind energy. This study is motivated to design a reliable FIV-WEH assembly in a wind farm, and to understand the altered environmental flow and disturbed output performance through large-eddy simulations and wind tunnel experiments, for the sake of harnessing fluctuating near-ground wind energy efficiently. The results demonstrates that the proposed eco-friendly FIV-WEH assembly has less impact on the surroundings due to the fast recovery of turbulent wake. Moreover, it is equipped with remarkable hysteresis caused by the delay of wake transition from 2P to C mode, which can enhance the output power, effective wind band, and more importantly, resilience. The resilience guarantees that the FIV-WEH assembly can harvest the fluctuating wind resources optimally even under strong turbulence intensity. Specifically, compact FIV-WEH assembly (l < 1.5, where l is dimensionless streamwise span) based on extended-body regime has a low cut-in speed (3 m/s), showing great potential to harvest breeze energy in a near-ground residential environment. Loose FIVWEH assembly (1.5 < l < 5) based on reattachment regime has a large cut-in speed (9 m/s) and low span sensitivity, which can be flexibly adjusted to extract the wind energy in spacious wind-abundant areas. Finally, two strategies developed by modifying surfaces of FIV-WEH assembly can further enhance the resilience and conversion efficiency by approximately 200%.(c) 2022 Elsevier Ltd. All rights reserved.