Wen-Yang Hsu

Elastic plate as floating wave breaker in a beach zone

Wave propagation and damping mechanism due to elastic coating of the sea surface is considered. The hydrodynamic performance of an elastic plate is analyzed for various conditions in terms of wave reflection and transmission, plate deflection, and surface strain. Rigidity and geometrical scales of the coating plate essentially affect the wave transmission characteristics. The model of wave propagation and scattering is constructed in the long-wave approximation. The case of elastic plate with fixed edges is considered. It is shown that optimally designed horizontal flexible membrane can be a very effective wave barrier in a beach zone.

Discrete evolution of the surface wave spectrum on a nonuniform adverse current

The major aim of this study is experimental verification and theoretical modeling of the modulation instability during the fast evolution of steep surface waves in the presence of an adverse current. One or several times, the maximum of the wave spectrum moves discretely to the low-frequency range. The adverse current intensifies and accelerates this process.

Laboratory and modeling study on modulated wave properties

Development of Benjamin−Feir instability is investigated under laboratory conditions and by analytical modeling. Nonlinear properties of the wave train with discrete spectrum are also investigated. The mechanically generated waves are composed of several discrete waves, while the newly generated harmonics are still combined into discrete spectra with the same frequency step. The technique proposed in this study allows us to study accurately the nonlinear variations in main properties of each harmonic with fixed frequency, such as amplitude, phase speed, and wavenumber along the wave tank together with velocities of wave packet crests, especially for the large transient waves. The phase speeds of short waves increase near large transient waves, and the velocities of longer waves are close to the values determined by the linear theory of waves. The relative long wave accompanied by short waves can dramatically change the local kurtosis and skewness of the wave field. They may play an important role for the generation of large transient wave and provide an opportunity for triggering of the freak waves.