LIU PHILIP L-F - Böcker

The aim of this review series is to present critical commentaries on knowledge in the field of coastal and ocean engineering. Each article will review and illuminate the development of the scientific understanding of a specific engineering topic. Critical reviews on engineering designs and practices in different countries will also be included. The first volume of the review series is a collection of five papers reviewing a wide range of research topics in coastal engineering.The first paper, written by Yeh, discusses one of the fundamental issues concerning many fluid flow problems, namely, free surface boundary conditions. In the second paper, a survey on another boundary dynamics, the seafloor dynamics is presented. Foda reviews recent studies on the nonlinear wave energy transfer into the seabed and different modes of wave-induced sediment fluidization processes in cohesive as well as in noncohesive seabeds. Several issues concerning the interactions between sediment deposit and marine structures, such as pipeline and breakwater, are also briefly reviewed. One of the active research areas in modeling wave propagation is the construction of a unified model which is valid from deep water to shallow water. Liu discusses several existing models. The sediment movement in the surf zone is a complex system. It can usually be decomposed into the longshore and the cross-shore components. Dean focused his discussion on the cross-shore sediment transport process. In the last paper, van der Meer presents a comprehensive review of the design consideration for a rubble mound breakwater. Both hydraulic and structural responses are discussed. Design formulas and graphs are presented, which can be used for a conceptual design of rubble mount breakwater.

This volume contains six papers discussing coastal processes, and physical and numerical modeling.In the first paper, Svendsen and Putrevu give an extensive review on the state of understanding of surf-zone hydrodynamics, including subjects such as wave breaking, wave-induced currents, and instability of nearshore currents and infragravity waves. They point out that the most urgent need is to develop an adequate theory for wave breaking and broken waves in the surf zone.One of the methods for studying the complex coastal processes is to perform laboratory experiments. However, physical models are always plagued by scale and laboratory effects, because the coastal process involves many different length and time scales. In the second paper, Kamphuis presents a detailed discussion on the sources and implications of the scale and laboratory effects on physical modeling.The third and the fourth papers are two parts of the discussion on the mathematical modeling of the meso-tidal barrier island coasts. To understand the dynamics of coastal inlet systems, one can either rely on empirical knowledge and construct various forms of empirical and semi-empirical models (Part I), or develop a set of mathematical models based on the physical processes (Part II). Although these models do not provide the details of the dynamics, they give valuable knowledge of the equilibrium-state relationships. de Vriend and Ribberink give a detailed review on two models, Initial Sedimentation/Erosion models and Medium-Term Morphodynamic models. They have also presented many examples of applications.In the fifth paper, Houston gives a brief review on different methods to mitigate beach loss caused by storms or persistent long-term erosion. He then describes, in detail, the method of beach nourishment, which is also called a beach fill. This paper discusses the information that must be collected to design a beach fill and that should be monitored after the completion of the project.The last paper of this volume shifts our attention to the design of offshore structures, such as gravity structures, floating barges and tankers. Chakrabarti discusses the effects of the uniform and shear currents on fixed and floating structures.

This review volume, the third in the series, presents the latest topics for discussion, which provides invaluable information to coastal and ocean engineers around the world. In the first paper of this volume, entitled “Internal Solitary Waves”, Grimshaw reviews the basic theory of weakly nonlinear waves in an incompressible density-stratified fluid. The internal solitary waves solutions and effects such as friction, refraction and finite amplitude on internal solitary waves are also discussed. In the second paper entitled “The 3/2-Power Law for Ocean Wind Waves and Its Applications”, Toba gives a thorough review on the field evidence and physical background of the 3/2-power law and the associated wind-wave energy spectra. Several wind-wave prediction models are also discussed. Goda, in his paper entitled “Directional Wave Spectrum and Its Engineering Applications”, gives a brief historical overview of the development of directional wave spectrum. He presents several standard formulas for directional spreading function for engineering applications and discusses the effects of directional spreading on nearshore currents and wave forces on coastal structures. In a companion paper entitled “Analysis of the Directional Wave Spectrum from Field Data”, Hashimoto describes the maximum entropy principle method, Bayesian directional spectrum estimation method and the extended maximum entropy method for estimating directional wave spectrum. Hashimoto also introduces a new developed Doppler-type directional wave meter for field measurements. Finally, in “Reliability-Based Design of Coastal Structures”, Barcharth introduces a design procedure that makes it possible to optimize a design and/or to design to a specific failure probability level.

This volume consists of five excellent review papers. In the first paper, “A Review of Coastal Wave Modeling: The Physical and Mathematical Problems”, N E Huang presents a summary of the state-of-the-art of wave modeling in deep waters. He points out several shortcomings in existing modeling approaches and expresses the urgent need for developing a statistical theory of surface waves in shallow waters. Huang believes that the statistical theory can be formulated as the soliton turbulence. He also points out other important issues in wave modeling, including the air-sea interaction processes, and the physics of the wave-current and dissipation processes. In the second paper A C Radder focuses his discussion on the “Hamiltonian Dynamics of Water Waves”. He demonstrates that the Hamiltonian theory of surface waves can be formulated in terms of surface elevation and the velocity potential at the free surface as canonical variables. Several evolution equations, can be readily obtained. Radder also points out the need to develop a stochastic wave model in the shallow-water environment.The maximum runup is arguably the single most important parameter in the design of coastal structures and for the evaluation of the inundation potential of storm surges and tsunamis. C E Synolakis presents a thorough review of the “Exact Solutions of Shallow-Water Wave Equations”. For a single sloping beach, the evolution and runup of solitary, dipole, N and cnoidal waves are discussed. These solutions are then extended to more practical problems.The last two papers concern the flow and sediment motions near the seafloor. In their paper, “Boundary Layer and Sediment Dynamics Under Sea Waves”, P Blondeaux and G Vittori give an expert review of the recent contributions on the understanding of the interaction of the coherent vortex with cohesionless or partially cohesive sediments in a boundary layer. The formation and development of small-scale bedforms in the coastal regions are also discussed. Finally, in “Wave Scour Around Structures”, B M Sumer and J Fredsøe review the scouring processes around various types of structures. Many recent experimental data and theoretical developments are presented.

In the last two decades, one of the most important research accomplishments in coastal hydrodynamics has been the development of accurate numerical models for nonlinear water wave propagation over a complex bathymetry from a relatively deep-water depth into the surf zone. This book contains five excellent papers reviewing different methodologies in various aspects of wave modeling; the authors are active researchers who have made original contributions to these subjects.

This invaluable volume consists of five articles covering a wide range of topics in coastal engineering. The reader can find a paper discussing the modern optical measurement techniques applied to wave studies. An introductory paper on wavelet theory provides readers with a new perspective on coastal and ocean engineering data analysis. For those who are interested in wave modeling, a review article on the stochastic evolution models is included. A detailed review paper on the recent sediment transport research should supply enough motivation for more research in this area. Finally, readers who are interested in history can find an interesting article reviewing the coastal development and coastal engineering activities in Japanese history.

This invaluable volume consists of five articles covering a wide range of topics in coastal oceanographic engineering. The reader can find an article discussing the modern bubble measurement techniques applied to field studies of bubble dynamics in coastal shallow water. A comprehensive review paper on nonlinear modulation of water waves provides readers with a new perspective on nonlinear processes in the coastal and ocean wave environment. For those who are interested in wave modeling, there are two review articles discussing various wave models, which can be used to study wave-structure interactions and harbor oscillations. Finally, readers who are interested in the subject of stratified flows can find an article presenting the detailed laboratory observations of lock-exchange flows.