Dynamics and performance evaluation of a vortex-induced vibration energy harvester with hybrid bluff body

Abstract

To investigate the influence of bluff body with a variable section on the vortex-induced vibration energy harvesting performance, a series of hybrid cylinders are designed and a quantitative comparison is presented. The basic elements of hybrid bluff body are the D-shaped (D) and original circular-shaped cylinders (O), and the length ratio between the O-shaped part and the D-shaped part is fixed. According to the arrangement order, three kinds of hybrid bluff bodies are termed as ODO, ODODO and DOD. A distributed model is developed and the numerical simulation is carried out to verify the response. Corresponding wind tunnel experiments are conducted, and the results reveal that compared to the bluff body with a circular cylinder, the hybrid bluff bodies such as ODODO and DOD can enhance the vortex-induced vibration and thus increase the output significantly. Moreover, the lock-in regions with the ODODO and DOD shapes will increase by 12.5% and 62.5%, respectively. However, the results also indicate that some type of arrangement such as ODO will suppress the energy harvesting performance. Furthermore, the computational fluid dynamics (CFD) method is employed to reveal the physical mechanism of flow field around the hybrid bluff body. The results show that the integration of D-shape prism in a cylinder along an axial direction could influence aerodynamics. A faster boundary layer separation occurs for the VIV energy harvesters with the hybrid cylinders of ODODO and DOD, which could improve the energy conversion efficiency from flow-induced vibrations. However, the aerodynamic force is restricted and response is suppressed as a D-shaped cylinder is sandwiched between two O-shaped cylinders.

A multi-directional and multi-modal galloping piezoelectric energy harvester with tri-section beam

“…In the natural environment, the direction and speed of the wind is generally time-varying. Although the cylinder bluff body can induce VIV from all directions thanks to its geometric characteristics, the classical VIV-based harvester with a straight beam as the supporting structure has restrict the direction adaptivity [15,16]. To widen the operational direction range and enhance the output performance, Wang et al [17] and Shi et al [18] proposed the cross-coupled dual-beam VIV energy harvester design in which a cylindrical bluff body was supported by two series-connected beams with bending directions perpendicular to each other, and it can work in two incident wind directions.…”

Analysis of clamped-clamped piezoelectric energy harvester under vortex induced vibration considering the stretching effect

“…Their experiments results showed that the synchronization regions of the bottom, top, and horizontal configurations are almost the same at low wind speeds, and the vertical configuration has the highest wind speed for synchronization with the largest harvested power. The effect of hybrid bluff bodies on VIV energy harvesting performance has been investigated in Li et al (2023). They considered the hybrid bluff body as a combination of two kinds of bluff elements, that is, O-shaped cylinder and D-shaped prism.…”

“…The literature review shows that the main element of piezoelectric energy harvesters are often a cantilever beam with a bluff body in its tip. Therefore, the nonlinear effect due to middle layer stretching effect has been neglected in the previous works (Abdelkefi et al, 2012;Akaydin et al, 2010;Dai et al, 2016;Ewere and Wang, 2014;Gao et al, 2013;Hou et al, 2020Hou et al, , 2022Jia et al, 2018;Li et al, 2022aLi et al, , 2022bLi et al, , 2023Ma et al, 2023;Mehmood et al, 2013;Rezaei and Talebitooti, 2019;Seyed-Aghazadeh et al, 2020;Skop and Griffin, 1973;Sui et al, 2022;Sun et al, 2019;Wang et al, 2020;Yang and He, 2019;Zhang et al, 2022;Zhang and Wang, 2016;Zhao et al, 2012Zhao et al, , 2016Zhao et al, , 2019.…”