title: Wave energy devices with compressible volumes.
abstract: We present an analysis of wave energy devices with air-filled compressible submerged volumes, where variability of volume is achieved by means of a horizontal surface free to move up and down relative to the body. An analysis of bodies without power take-off (PTO) systems is first presented to demonstrate the positive effects a compressible volume could have on the body response. Subsequently, two compressible device variations are analysed. In the first variation, the compressible volume is connected to a fixed volume via an air turbine for PTO. In the second variation, a water column separates the compressible volume from another volume, which is fitted with an air turbine open to the atmosphere. Both floating and bottom-fixed, axisymmetric, configurations are considered, and linear analysis is employed throughout. Advantages and disadvantages of each device are examined in detail. Some configurations with displaced volumes less than 2000 m3and with constant turbine coefficients are shown to be capable of achieving 80% of the theoretical maximum absorbed power over a wave period range of about 4 s.
authors.affiliation: School of Marine Science and Engineering, Plymouth University , Plymouth PL4 8AA, UK.
authors.forename: Adi
authors.identifier: 0000-0002-9176-3702
authors.initials: A
authors.lastname: Kurniawan
authors.affiliation: School of Marine Science and Engineering, Plymouth University , Plymouth PL4 8AA, UK.
authors.forename: Deborah
authors.initials: D
authors.lastname: Greaves
authors.affiliation: Faculty of Engineering and the Environment , University of Southampton , Southampton SO17 1BJ, UK.
authors.forename: John
authors.initials: J
authors.lastname: Chaplin
keywords: absorbed power; axisymmetric device; compressible volume; numerical modelling; wave energy