| Abstract | Submerged protection structures are frequently used in coastal engineering applications, such as tunnel and pipeline protection works, breakwaters, and artificial reefs. Although significant progress has been achieved in research on low-submergence coastal structures, there is far less research on deeply submerged structures. Moreover, most of the research efforts have been directed towards gently-sloped and uniformly cross-sectioned structures with a specific, fixed crest elevation. The paper presents the results and analysis of a collaborative research project conducted by the University of Ottawa and the Canadian Hydraulics Centre (CHC) which involved large-scale three-dimensional physical modelling project and computer simulations. The main aim of the research was to understand the effect of a three-dimensional submerged structure on local wave conditions, orbital velocities and wave-induced circulation. The numerical simulations were performed using the non-linear Boussinesq wave model named WaveSim, developed at CHC (Nwogu, 1996). Analysis was performed on a multitude of physical and numerical data, including, but not limited to, wave heights, wave periods, wave energy spectra, energy transfer functions, reflection analyses, and wave-induced velocities. It was observed that the submerged structure significantly changed the wave climate and generated substantial modifications to the wave-induced velocities along the structure’s crest. The transfer function analysis showed distinct patterns in energy transfer between the up-wave and down-wave gauges, specifically a significant reduction in energy around the spectral peak frequency and a significant increase in energy at double the spectral peak frequency. The spatial distribution of significant wave height was found to have a distinct pattern, with peaks occurring at approximately every half wavelength. Reflection analysis showed a clear relationship between the amount of reflected energy and the submergence depth of the structure. |
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