In this unique volume the authors review the development of the subject, virtually from its inception. Details of much of the research work carded out in the linearized theory of water waves concerning problems of water wave scattering by barriers is incorporated.

The theory of water waves is most varied and is a fascinating topic. It includes a wide range of natural phenomena in oceans, rivers, and lakes. It is mostly concerned with elucidation of some general aspects of wave motion including the prediction of behaviour of waves in the presence of obstacles of some special configurations that are of interes

This dissertation, "Wave Transformation Due to Vertical Barriers in Fluids" by Man-yip, Mark, Lee, 李文業, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled Wave transformation due to vertical barriers in fluids Submitted by Mark Man-yip Lee for the degree of Doctor of Philosophy at The University of Hong Kong in June, 1998 Theoretically investigation on the various wave transformation problems involving vertical barriers in fluids are conducted in a attempt to consolidate the understanding of the vertical barrier's interactions with water waves. In this first part of the present work, two categories of the wave transformation problems are focused on, which are the wave scattering and wave radiation problems. The problems of wave scattering due to vertical porous barriers immersed in a homogeneous fluid of finite depth are considered first. For this class of two-dimensional problems, it is sensible to adopt the method of eigenfunction expansion so as to take advantage of the simplified geometry involved and the ease of analyzing the effects of changes in the parameters. The amplitudes of the scattered waves, involving both the transmitted and reflected waves, are determined for the case of monochromatic incoming waves. The performance of the porous barriers of four different basic configurations are studied by examining the characteristic in the variation of their transmission and reflection coefficients, impinging wave force, moment, etc., under different conditions. It is found that in general an increase in the porosity of the barriers results in the decrease of wave amplitudes, wave force, wave moment, etc. The wave radiation problems in a homogeneous fluid of finite depth are investigated by using the same eigenfuction expansion method to determine the amplitude to stroke ratios for the three different types of wavemakers, which essentially are oscillating porous plate. The results for the particular case when the porous wavemaeker extends fully from the bottom to the free surface are in good agreement of the earlier exact analytical work by Chwang (1983). Two-layer fluids are subsequently introduced to these wave scattering and radiation problems. The problems of waves scattering due to a vertical impermeable barrier inserted between a single-layer fluid and a two-layer fluid are investigated for two different kinds of barriers. The results reveal that two distinct scattered wave modes exist in the two-layer, which explains why there was a discrepancy in the theoretical prediction of oil thickness variation near an oil retention boom with the experimental results in the earlier work by Kordyban (1992). The problems of wavemakers in a two-layer fluid are also examined for two categories: piston-type and flap-type. The results show that the flap-type wavemakers are more effective in generating surface waves than the piston-type wavemakers. In the second part of this work, the unsteady problems of oil spreading on a water surface are investigated analytically for both two- and three-dimensional cases. Two specific effects, the effect of water currents and the effect of water waves, on the spreading are investigated. It is demonstrated that both effects will causes the oil to spread faster in the propagating direction of the currents or waves. DOI: 10.5353/th_b2981278 Subjects: Wave mechanics

The theory of water waves is most varied and is a fascinating topic. It includes a wide range of natural phenomena in oceans, rivers, and lakes. It is mostly concerned with elucidation of some general aspects of wave motion including the prediction of behaviour of waves in the presence of obstacles of some special configurations that are of interest to ocean engineers. Unfortunately, even the apparently simple problems appear to be difficult to tackle mathematically unless some simplified assumptions are made. Fortunately, one can assume water to be an incompressible, in viscid and homogeneous fluid. The linearised theory of water waves is based on the assumption that the amplitude of the motion is small compared to the wave length. If rotational motion is assumed, then the linearised theory of water waves is essentially concerned with solving the Laplace equation in the water region together with linearised boundary condition. There are varied classes of problems that have been are being studied mathematically in the literature within the framework of linearised theory of water waves for last many years.

Mathematical Techniques for Wave Interaction with Flexible Structures is a thoughtful compilation of the various mathematical techniques used to deal with wave structure interaction problems. The book emphasizes unique determination of the solution for a class of physical problems associated with Laplace- or Helmholtz-type equations satisfying higher order boundary conditions with the applications of the theory of ordinary and partial differential equations, Fourier analysis, and more. Features: Provides a focused mathematical treatment for gravity wave interaction with floating and submerged flexible structures Highlights solution methods for a special class of boundary value problems in wave structure interaction Introduces and expands upon differential equations and the fundamentals of wave structure interaction problems This is an ideal handbook for naval architects, ocean engineers, and geophysicists dealing with the design of floating and/or flexible marine structures. The book’s underlying mathematical tools can be easily extended to deal with physical problems in the area of acoustics, electromagnetic waves, wave propagation in elastic media, and solid‐state physics. Designed for both the classroom and independent study, Mathematical Techniques for Wave Interaction with Flexible Structures enables readers to appreciate and apply the mathematical tools of wave structure interaction research to their own work.