City Research Online

Abstract

This paper extends a hybrid model qaleFOAM to assess the nonlinear interaction of waves with an array of point-absorber wave energy converters (WECs). The hybrid model uses an adaptive one-way coupling strategy, combining a two-phase Navier–Stokes (NS) solver interDyMFoam with the fully nonlinear potential theory (FNPT)-based solver QALE-FEM. To minimise the computational cost, an improved wave absorbing technique is adopted to absorb the undesirable reflected waves at the inlet/outlet boundary of the NS domain instead of using the conventional relaxation zone technique. The model is first assessed against available single-buoy benchmark data, and then applied to regular head-wave cases involving CorPower-type buoys arranged in line arrays. The effects of wave steepness, PTO damping and non-dimensional array spacing are examined. For the two-buoy cases, increasing wave steepness increases the mean surge and pitch drifts and enhances the asymmetry of the instantaneous absorbed power, while reducing the normalised first-harmonic motion amplitudes. Increasing PTO damping reduces the heave response but increases restraint forces and power fluctuations, and may promote overtopping under the studied conditions. For the three-buoy cases, the q-factor and the absorbed power of each buoy vary non-monotonically with non-dimensional spacing d/λ, with the minimum q-factor observed at d/λ≈0.5. Shorter waves produce stronger shielding effects on the middle and rear buoys, affecting both hydrodynamic loads and tether-force fluctuations. These results demonstrate that, within the tested configurations, nonlinear wave effects, PTO damping and array spacing can influence motion response, power absorption and load distribution among buoys.

Publication Type:	Article
Additional Information:	© The Authors. Published by Elsevier. This is an open-access article distributed under the terms of Creative Commons: Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/).
Publisher Keywords:	WEC; Array; Power performance; Nonlinear interaction; q-factor; qaleFOAM
Subjects:	G Geography. Anthropology. Recreation > GE Environmental Sciences Q Science > QA Mathematics > QA75 Electronic computers. Computer science T Technology > TA Engineering (General). Civil engineering (General) T Technology > TC Hydraulic engineering. Ocean engineering T Technology > TK Electrical engineering. Electronics Nuclear engineering
Departments:	School of Science & Technology School of Science & Technology > Department of Engineering
SWORD Depositor:	Symplectic Administrator

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