Load assessment of optimally-arranged point absorbers arrays in front of a vertical wall

Abstract

In this paper, we assess numerically the loads applied on PAs of optimally-arranged linear arrays in front of a bottom-mounted vertical wall of finite length under normal operating conditions. The arrays, maximizing the yearly absorbed energy, consist of five, identical, oblate spheroidal heaving PAs and are deployed at three near-shore sites in the Aegean Sea, Greece. The PAs are assumed to be attached on the wall via connection configurations restraining all rigid-body modes except heave. A spectral analysis is performed to quantify loads. The corresponding transfer functions are obtained from a frequency-based hydrodynamic model that solves the diffraction/radiation problem of the multi-body arrangement in the presence of the wall. Results, focusing on surge and sway restraining loads, are, initially, presented for regular waves and, then, for normal operating conditions (irregular waves), highlighting the effect of the arrays’ layouts and of the local wave conditions on the restraining loads. Comparison is also made with equally-spaced arrays to reveal potential positive effects of optimum layouts on structural integrity related issues.