Hydrodynamic interactions of oscillating wave surge converters in an array under random sea state

Abstract

The oscillating wave surge converter (OWSC) type devices (e.g., an Oyster wave energy converter) generate electric power via rotating motion about the bottom of the device. This type of wave energy converters have a wide power absorption bandwidth which enables the electricity generation at a wide range of wave frequencies. The power produced by the OWSCs could be maximised by configuring individual devices within an array. This paper examines the power production performance of multiple OWSCs in an array under regular, unidirectional irregular wave and multi-directional sea using the industry standard hydrodynamic software WAMIT. The performance of the OWSC array is represented as q-factor, which is a quantity defined as the ratio of the average total power produced in an array to the power produced by an individual OWSC. The results show that the OWSCs arranged in an array would produce both constructive and destructive interferences depending on the wave directions and frequencies. Further, the spreading function, the resonance bandwidth and the optimal spacing between the devices are shown to affect the performance of the OWSC 2 significantly. The results provide an enhanced understanding of the behaviour and performance of the OWSCs when arranged in an array of different configurations.

Advances and Challenges in Wave Energy Park Optimization—A Review

“…Several commercial (Lee, 1995;AQWA, 2013) and open-source BEM software packages (Babarit and Delhommeau, 2015) exist. BEM software has also been coupled to wave propagation models such as MILDwave or OceanWave3D to study the perturbed wave field in a larger ocean area with varying bathymetry (Verbrugghe et al, 2017;Verao Fernández et al, 2018, 2019 and are further developed and used extensively to model the hydrodynamical interaction in wave energy parks (Sinha et al, 2016;Ruiz et al, 2017;Tay and Venugopal, 2017;Bosma et al, 2019;Lyu et al, 2019).…”

“…Layout optimization by sweeping over parameters such as separation distance and angles between devices was performed by Snyder and Moarefdoost (2015) and Göteman et al (2015a). The power production of arrays of 12 OWSCs was studied in both regular, long-crested, and shortcrested waves by Tay and Venugopal (2017), and the interaction function was evaluated as a function of the separation distance between devices. Also, parameter sweeps to determine the impact of wave parameters such as wave number, wave direction, and significant wave height has also been conducted in a number of works, including Konispoliatis and Mavrakos (2016)…”

“…An array of 25 WEC models was studied experimentally in short-crested waves by Stratigaki et al (2014), and it was found that the wave height decrease occurred earlier than in corresponding long-crested waves. Tay and Venugopal (2017) studied the interaction factor of a park of 12 OWSCs in short-crested wave spectra, and it was found to be slightly lower than in long-crested waves. The performance of an array of 16 WECs in short-crested waves was studied by Göteman et al (2018), and it was concluded that the energy absorption was comparable to the situation in long-crested waves, whereas the power fluctuations were considerably lower.…”

Arrays of Point-Absorbing Wave Energy Converters in Short-Crested Irregular Waves

“…A useful measure of the power fluctuations in a park is given by the variance (6). However, low fluctuations is only one measure of good park performance; in addition, large energy absorption is required, which can be quantified in terms of the normalized energy absorption (7). An optimal park will have a high energy absorption and low power fluctuations, simultaneously.…”

“…Since the early works on wave energy, studying and optimizing wave energy array layouts have been main topics of interest [1][2][3], and remains an active area of research today [4][5][6][7][8][9].…”