A Novel 2-D Point Absorber Numerical Modelling Method

Abstract

Despite several wave energy converters (WECs) having been developed to present, no particular concept has emerged yet. The existing inventions vary significantly in terms of the operation principle and complexity of WECs. The tethered point absorbers (PAs) are among the most known devices that, thanks to their simplicity, appear to be cost-effective and reliable for offshore installation. These devices need to be advanced further and, therefore, new tailored modelling methods are required. Numerical modelling of this type of WEC has been done mainly in one degree of freedom. Existing methods for multi-degrees of freedom analysis lack pragmatism and accuracy. Nevertheless, modelling of multiple degrees of freedom is necessary for correct analysis of the device dynamic response, wave loads and device performance. Therefore, an innovative numerical method for two degrees of freedom analysis of PA WECs, which permits precisely modelling the dynamics of PA for surge and heave motions, is introduced in this paper. The new method allows assessing, in the time-domain, the dynamic response of tethered PAs using regular and irregular sea states. The novel numerical model is explained, proved and empirically validated.

On the Development of a Near-Shore Pivoting Wave Energy Converter

“…Such variables need to be sufficiently long to correctly assess the hydrodynamic effects. In the case of small WECs such as the PWEC, casual and non-casual transient functions usually decay in about 30 s to 120 s, respectively [20].…”

“…Although it is, in general, challenging to validate the power output when small-scale models are used [19], if the model is big enough and correct experimental practices and equipment are implemented, reasonable measurements of wave loads and WEC motions can be obtained. Examples are provided in [20][21][22][23], where different WECs have also been studied using experimental methods.…”

Assessing the Effectiveness of a Novel WEC Concept as a Co-Located Solution for Offshore Wind Farms

“…Similarly, the values and analytical expressions proposed by Clark et al [30], for each of the sub-costs of Equation (15), are summarised in Table 6. Finally, decommissioning costs can be computed according to Equation ( 16).…”

“…Over the last two decades, a multitude of WEC concepts, based on different working principles, has been put forward. Among them, point absorbers (e.g., CorPower [14,15]), overtopping devices (e.g., Wavedragon [16] and Wavecat [17]), oscillating water columns [18,19], attenuators (e.g., Pelamis [20]), as well as oscillating wave surge (e.g., Oyster [21]) and submerged differential pressure (e.g., CETO [22]) devices, stand out. However, the great majority of them are still present at low technology readiness levels, far from commercial viability [23].…”