Investigation of hydrodynamic performance of an OWC (oscillating water column) wave energy device using a fully nonlinear HOBEM (higher-order boundary element method)

An Experimental Study of Pile-Supported OWC-Type Breakwaters: Energy Extraction and Vortex-Induced Energy Loss

“…However, if the purpose of the OWC structure is to reduce transmitted waves, vortex-induced energy loss is beneficial to the total energy dissipation and can improve the wave protection performance. To date, most of the studies of OWC focus on the energy extraction (e.g., [23][24][25][26][27][28][29]), and there have only been a few earlier studies touching upon the vorticity characteristics of OWC (e.g., [30][31][32]). Analytical and numerical studies based on potential theory are with certain limitation in dealing with viscous effects, while numerical studies based on viscous flow theory need experimental results for validation.…”

Numerical Simulation of a Dual-Chamber Oscillating Water Column Wave Energy Converter

“…For each case, 30 wave periods are simulated with a time step of ∆t = T/80. More information about the numerical model can be found in references [11,17].…”

“…To simplify the simulation, the potential fluid theory is adopted. An artificial damping coefficient µ 2 is applied to the free surface condition inside the chamber to model the viscous effect due to the water viscosity and flow separations [11]. Then, the fluid is assumed to be incompressible, inviscid, and the fluid motion is irrotational.…”

“…To investigate the hydrodynamic performance of the proposed dual-chamber OWC device, the two-dimensional fully nonlinear numerical model based on the potential theory and the time-domain HOBEM by Ning et al [11] is extended here to simulate the interaction of the wave and the dual-chamber OWC device by adding a barrier wall in the single chamber device. The sketch of the flume is shown in Figure 1.…”

“…This internal pressure fluctuation runs the air above the internal free surface inside the enclosed chamber through the turbine, which eventually drives the electrical generator to produce electricity. A great volume of researches has been carried out to investigate the efficiency of OWCs analytically [4][5][6][7], numerically [8][9][10][11][12] and experimentally [13][14][15][16][17][18][19], most of which focus on the single chamber device. Generally, for a single chamber OWC, it has been recognized that if the device is to be an efficient absorber, it should operate at near-resonance conditions [20][21][22][23].…”