It has become known that a curtain-wall type dissipater of reflected waves from vertical sea walls and breakwaters is more effective for comparatively long waves than the conventional perforated walls and breakwaters. The dissipation mechanism of reflected waves is to enhance vortex flows around a vertical barrier by the use of piston-mode wave resonance in the water chamber. However, for the sea with large tidal difference, it is concerned that effectiveness of the reflection dissipater may vary significantly with tidal levels because the draft depth of the vertical barrier changes with tidal levels.
In this study, at first, variations of effectiveness of a curtain-wall type dissipater with tidal levels were clarified by both the physical model test and theoretical study. Secondly, in order to overcome such difficulties resulted from varying tidal levels, two different counter measures were proposed. Effectiveness of these measures was also examined theoretically and experimentally.
