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This paper investigates wave-current-structure interaction considering both the following and opposing current. Experiments were conducted in a wave flume to determine wave transformation characteristics (i.e. wave reflection, transmission, and dissipation) employing both regular and irregular waves propagating in the presence of smooth and rough breakwaters. Discrepancies in the wave transformation characteristics are observed between smooth and rough breakwaters with and without currents. Transmission coefficient differences between smooth and rough structures were 33% and 12% for the regular and irregular waves, respectively. Reflection coefficients in irregular waves are more sensitive than in regular waves. However, the influence of external current on the energy loss coefficient was not significant when the submerged breakwater height increased. [ABSTRACT FROM AUTHOR]

In this study, we investigated the energy dissipation characteristics of stepped obstacles by using both the regular and irregular waves in a physical wave flume. The stepped obstacle used in this study is different from those of traditional stepped dikes with fixed horizontal and vertical stage surfaces; here, the angle of the stepped surface varies with the slope of the embankment surface, with various interaction angles between the incident waves and the rough stepped surfaces. The stepped embankments were composed of six types of stepped arrangements and were used to analyse the wave run-up heights and reflection coefficients; in addition, the variations in energy dissipation effects were also studied. The results identify two of the six roughness types that have better mitigation effects on the investigated the energy dissipation characteristics of stepped obstacles. The reflection coefficient is larger for a submerged dike with a rough surface than for one with a smooth surface. [ABSTRACT FROM AUTHOR]

This study reports physical experiments conducted with various combinations of undulating breakwaters under various wave conditions. The preliminary analysis consists of wave attenuation characteristics and efficiency of various combinations of sinusoidal breakwaters estimated by the transmittance, the variation in reflectance and loss coefficient, and the optimisations of a variety of sinusoidal breakwaters. The interaction of surface waves scattered by undulating ocean floor topography, such as sinusoidal bars, is of fundamental importance to sediment transportation. Thus, this study investigates the characteristics of multi-array impermeable sinusoidal submerged breakwaters experimentally. The interaction between waves and the obstacles are also investigated using the reflection coefficient, transmitted coefficient, and attenuation of wave energy. Most of the related investigations conducted theoretically and experimentally for the predictions of the propagation of water waves over the undulating ocean floor topography have focused on the problems of Bragg resonance. Specific parameters could be suitably chosen to control the resonance; composite artificial obstacles with specific parameters, which reduced the intensity of transmitted waves, may be used to protect beaches. Therefore, this study discusses the properties of the reflection coefficient of the sinusoidal breakwaters, the attenuation caused by the varying combinations of submerged obstacles, the effectiveness of wave attenuation, and the optimisation of the disposition of sinusoidal breakwaters. [ABSTRACT FROM PUBLISHER]