Laboratory and numerical experiments on stem waves due to monochromatic waves along a vertical wall

Abstract

Abstract. In this study, both laboratory and numerical experiments are conducted to investigate stem waves propagating along a vertical wall developed by the incidence of monochromatic waves. The results show the following features: for small-amplitude waves, the wave heights along the wall show a slowly varying undulation. Normalized wave heights perpendicular to the wall show a standing wave pattern. The overall wave pattern in the case of small-amplitude waves shows a typical diffraction pattern around a semiinfinite thin breakwater. As the amplitude of incident waves increases, both the undulation intensity and the asymptotic normalized wave height decrease along the wall. For largeramplitude waves with smaller angle of incidence, the measured data clearly show stem waves. Numerical simulation results are in good agreement with the results of laboratory experiments. The results of present experiments favorably support the existence and the properties of stem waves found by other researchers using numerical simulations. The characteristics of the stem waves generated by the incidence of monochromatic Stokes waves are compared with those of the Mach stem of solitary waves.

Flow Characteristics of the Rip Current System near a Shore-Normal Structure with Regular Waves

“…Comparing to the case of α = 30 • , the reflection wave area becomes smaller and the standing wave length becomes larger for the smaller angle α = 15 • , so there is only one theoretical node and one node rip appearing in the inner domain. More important is that there is a stem wave appearing (see Yoon et al [46] for the stem wave), which has the width about half the longshore extent of the reflection wave area. This leads to the 1st node deviating away largely from the theoretical node line by about half the standing wavelength and the flow pattern of inner domain mainly characterized by a single large-scale vortex, with the larger offshore directed velocity of the vortex serving as the node rip current.…”