TY - JOUR TI - The effects of submergence depth on energy harvesting from the VIV of a four-cylinder oscillator with rigid connection AU - Yang, T AU - Luo, Z AU - Yu, F AU - Li, J AU - Gao, S T2 - Journal of Renewable and Sustainable Energy AB - Numerical and experimental studies of energy harvesting driven by vortex-induced vibration (VIV) are currently focused on arranging the energy-captured structure in a uniform incoming flow at a certain depth, ignoring the effect of the free surface on VIV. The fluid–structure coupling effect can be enhanced when a column-group structure with rigid connection is arranged under uniform flow, which is helpful for the structure to concentrate hydrokinetic energy from low-velocity water flow. In this paper, a staggered arrangement of a four-cylinder oscillator with rigid connections is proposed as the energy converter, and the fluid–solid interaction numerical method is carried out to simulate the VIV of the four-cylinder structure under single-phase flow and free surfaces. In U* = 2–16 (flow velocity U = 0.16–1.28 m/s), the results of the energy harvesting magnitude, efficiency, and density of the four-cylinder oscillator under the arrangement depth ratios S* = 2, S* = 3, S* = 4, and S* = 5 are compared with the results obtained in the single-phase flow. It was found that the column-group structure has a broader resonance range of VIV in single-phase flows than a single cylinder and can capture more hydrokinetic energy concentratedly from low-velocity flow. The VIV responses of the four-cylinder oscillator are suppressed at low submergence depths with a narrower resonance range, and its captured energy is reduced. In contrast, at high submergence depth ratio S*, the VIV responses are not suppressed obviously by the free surface. The magnitude of captured energy, energy-harvesting efficiency, and density of the four-cylinder structure are basically consistent with the results obtained in single-phase flow at S* = 5. DA - 2022/11// PY - 2022 PB - AIP Publishing VL - 14 IS - 6 SP - 14 UR - https://aip.scitation.org/doi/full/10.1063/5.0109454 DO - 10.1063/5.0109454 LA - English KW - Current KW - Vortex-Induced Vibration KW - Modeling KW - Hydrodynamics KW - Performance ER -