A Numerical Study on an Oscillating Water Column Wave Energy Converter with Hyper-Elastic Material

Abstract

A model different from the traditional WEC, known as the flexible wave energy converter (fWEC), is numerically modeled in this paper. The fWEC is believed to be more efficient and has a greater range of operation when compared with the conventionally rigid WEC. A fully coupled fluid–structure interaction (FSI) tool is developed for the research performed in this paper. This tool is able to accommodate the dynamic interaction between the flexible membrane structure of the fWEC and the surrounding fluid. In this research, both linear-elastic and hyper-elastic materials are examined for their use in the fWEC. The fluid flow surrounding the fWEC is solved by a computational fluid dynamics (CFD) method. The deformation of the hyper-elastic structure within the fWEC is modeled using a finite element analysis method (FEA). Both the hyper-elastic material of the fWEC and the free surface wave contribute to the overall nonlinearity of the numerical simulation. To tackle this problem, a robust coupling scheme is implemented by an advanced coupling library. With this tool, the flexible deformations within the fWEC structure can be accurately captured. The degree of these deformations can then further be examined, allowing the overall effects on the fWEC energy output to be determined. The simulation results show that the peak deformation of the hyper-elastic material is four times that of the linear-elastic material. This suggests that the fWEC would perform better and generate greater power using the hyper-elastic material compared with the linear-elastic material. Additionally, because a wide range of wave conditions are studied, it can be concluded that unlike conventional WECs, the efficiency of energy harvesting of such an fWEC is not sensitive to certain wave periods. Such findings are supported by both the detailed flow fields captured and the structural stress–strain analysis results from this simulation.

Evaluating the Applicability of Mainstream Wave Energy Converters in the South China Sea

“…The most common point absorbers are the AquaBuoy, Wavebob, and Archimedes Wave Swing (AWS). These systems are small in size, can capture wave energy from multiple directions, and have high conversion efficiency [31,32]. The most common OWCs include, for example, the WaveStar and OceanLinx, which both have strong stability in extreme environments but have high construction costs and low WEC efficiency [32].…”

“…These systems are small in size, can capture wave energy from multiple directions, and have high conversion efficiency [31,32]. The most common OWCs include, for example, the WaveStar and OceanLinx, which both have strong stability in extreme environments but have high construction costs and low WEC efficiency [32]. The typical representative device of an oscillating surge wave energy converter is RM5, which is a type of device that utilizes the surge motion of waves to generate electrical power [33].…”

“…There are two types of devices: floating and fixed. The floating device is fixed by a chain and can be transported and deployed in an area rich in wave energy to generate electricity [32].…”

“…When utilizing wave energy resources from a specific sea area, an appropriate WEC should be selected according to the suitable water depth of the device, output power, and other influencing factors. Table 1 briefly summarizes and presents the characteristic parameters of typical WEC types [31][32][33][34][35][36][37]. When evaluating the applicability of mainstream WECs for use in specific marine areas, it is necessary to use appropriate evaluation indicators.…”

Design and Evaluation of the Compact and Autonomous Energy Subsystem of a Wave Energy Converter

“…The WECs implementations involving the electrical generators have emerged [4][5][6][7][8][9] and their development is still ongoing [10][11][12]. Simultaneously, a new approach involving the use of new materials to convert mechanical vibrations of water waves into electrical form began to arise [13][14][15][16][17][18][19][20]. Some of these solutions proved the advantage-in certain applications-of the maintenance-free piezoelectric materials (PMs) over the solutions involving the electromechanical machines operating as generators.…”