We numerically analyze the flushing effects and the likelihood of a vertical breakwater consist of immersed water channel and water chamber, originally proposed by Nakamura (1999, 2003, 2005) for the alleviation of reflected waves, as a wave energy extraction measure. As a wave driver, we use the Nervier-Stokes equations and mass balance equation, and the numerical integration of which is carried out based on the smooth particle hydrodynamics with a Gaussian Kernel function. As a water level in front of curtain wall, where an anti-node of standing wave due to partial reflection is located, approaches its lowest level, a unidirectional flow in the water chamber formed by a preceding wave starts to move offshore. Once it exits water chamber, this energetic flow feeds necessary energy into the vortex in front of the water chamber to sustain long enough until next wave comes. Considering the facts that an intensity of the flow absorbed through the immersed water channel is strongly proportional with an extent and strength of the vortex formed on offshore side of front curtain wall and a curved path line of sucked water particles, we can deduce that aforementioned vortex is responsible for the flushing effects of the vertical breakwater consist of immersed water channel and water chamber. It is also shown that net flux through the immersed water channel increases as the mass inflow into a water chamber is getting larger (T=1.4sec, Le =6cm), which also confirm our conclusion.
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