Numerical study of an oscillating water column wave energy converters

Abstract

An oscillating water column (OWC) device is a renewable energy device whose structural part is a partially submerged chamber consisting of an air and a water column that oscillates vertically to extract energy from ocean waves. The operating principle of a OWC system includes complex hydrodynamic interactions between the waves and the structure that must be understood for the design of structurally sustainable and hydro-dynamically efficient system. The aim of this thesis is to investigate hydrodynamic efficiency of land-fixed and offshore OWCs through two-dimensional numerical simulations. The motion of the offshore OWCs on hydrodynamic efficiency is also examined by investigating effect of natural frequency ratio (Rf) (mooring) on OWC performance. Natural frequency ratio is defined as the ratio of the natural frequency of the elastically supported OWC to the wave frequency. In this study the fluid motion under waves is simulated by solving the two-dimensional incompressible Reynolds-Averaged Navier-Stokes (RANS) equations using the Arbitrary Lagrangian-Eulerian (ALE) scheme. In summary, Wave energy is an emerging technology and an exciting opportunity to generate green energy as an alternative renewable energy source. There are more than 200 wave energy devices in various stages of testing and demonstration. The worldwide resource of coastal wave energy has 178 been estimated to be greater than 2 TW. Locations with the most potential for wave power include the western seaboard of Europe, the northern coast of the UK, and the Pacific coastlines of North and South America, Southern Africa, Australia, and New Zealand. The north and south temperate zones have the best sites for capturing wave power. With this information in hand, the research on renewable energy to produce electricity from ocean wave will be the most significant source in Australia. Research shows wave energy could contribute up to 11 percent of Australia's energy (enough to power a city the size of Melbourne) by 2050, making it a strong contender in Australia's renewable energy mix. As the development of new different wave energy converters (WECs), such as oscillating water column (OWC) is one of the most promising wave energy converters to produce electricity from the ocean wave. The OWC device is more sustainable in the different offshore conditions and economically benefited in the world, Currently, Australia produces electricity by using OWC device in Tasmania and Brisbane Airport Corporation will be powered with 100 per cent renewable energy, as part of a landmark renewable energy agreement with government-owned energy generator.

Date of Award	2022
Original language	English