Wave power extraction from multiple oscillating water columns along a straight coast

Abstract

The integration of oscillating water column (OWC) wave energy converters into a coastal structure (breakwater, jetty, pier, etc.) or, more generally, their installation along the coast is an effective way to increase the accessibility of wave power exploitation. In this paper, a theoretical model is developed based on the linear potential flow theory and eigenfunction matching method to evaluate the hydrodynamic performance of an array of OWCs installed along a vertical straight coast. The chamber of each OWC consists of a hollow vertical circular cylinder, which is half embedded in the wall. The OWC chambers in the theoretical model may have different sizes, i.e. different values of the radius, wall thickness and submergence. At the top of each chamber, a Wells turbine is installed to extract power. The effects of the Wells turbine together with the air compressibility are taken into account as a linear power take-off system. The hydrodynamic and wave power extraction performance of the multiple coast-integrated OWCs is compared with that of a single offshore/coast-integrated OWC and of multiple offshore OWCs. More specifically, we analyse the role of the incident wave direction, chamber size (i.e. radius, wall thickness and submergence), spacing between OWCs and number of OWCs by means of the present theoretical model. It is shown that wave power extraction from the coast-integrated OWCs for a certain range of wave conditions can be significantly enhanced due to both the constructive array effect and the constructive coast effect.

Advances and Challenges in Wave Energy Park Optimization—A Review

“…modes (De Chowdhury and Manasseh, 2017;Wolgamot et al, 2017), interaction distance cut-off (Göteman et al, 2015a), a nearest neighbor approach (Sarkar et al, 2016), and Haskind's relation (Flavià and Clément, 2017) have been introduced. Both the iterative and non-iterative versions of the multiple scattering theory have been further developed and used to model the hydrodynamics of wave energy parks (Ji et al, 2015;Konispoliatis and Mavrakos, 2016;Göteman, 2017;Ruiz et al, 2017;Fang et al, 2018;Giassi and Göteman, 2018;Zheng et al, 2018Zheng et al, , 2019Liu et al, 2019). Several other analytical methods have been developed and used for wave energy park applications, including matched asymptotic expansions (McIver and Evans, 1988), multipole expansions (Linton and Evans, 1993), and Bragg scattering (Li and Mei, 2007).…”

Hydroelastic interaction between water waves and an array of circular floating porous elastic plates

“…After using Graf's addition theorem for Bessel functions (Abramowitz & Stegun 1972; Zheng, Zhang & Iglesias 2018; Zheng et al 2019), (3.1) can be rewritten in the cylindrical coordinates as …”

Design Selection and Geometry in OWC Wave Energy Converters for Performance

“…In addition, many studies investigate the performance improvements that specific geometric modifications introduce in an OWC converter, e.g., variations in the slope of the front and rear walls of the chamber [19], or the effects of the length and the opening angle of harbor walls (a pair of sidewalls in front of the device) [20]. Finally, OWC technology lends itself to the installation of multiple chambers, integrated e.g., in floating platforms or deployed along the coast as part of a structure [21,22]. In all the mentioned cases, both on the offshore and the nearshore OWC devices, the optimization of the chamber geometry has to be carried out taking into account the wave climate at the locations of interest, being necessary to characterize the wave conditions that provide the bulk of energy (e.g., [23][24][25]).…”