Morphodynamic variability of surf zones and beaches: A synthesis

This book offers a comprehensive manuscript encompassing two separable texts on hydrodynamics and control of marine vehicles. In contrast to the aerospace industry, where dynamicists are often control experts as well, in the maritime world (due to the significant effect environmental loads have on the dynamics of the system) the more common pairing is dynamics with hydrodynamics. As such, Fossen is one of few in the maritime industry who could write such a complete treatment of dynamics, hydrodynamics, and control issues related to surface and subsurface marine vehicles. The author provides an excellent treatment of the subject matter, written from a more generalist perspective, at a substantially lower cost. There are excellent texts covering marine hydrodynamics, vessel dynamics, and ship motion control. However, for some time a void has existed in the literature covering the intersection of these related fields, with the exception of specialist texts such as the treatment of high-speed craft control. Contents This book is presented as two volumes. The first volume is devoted to marine craft hydrodynamics and the second volume of the book is devoted to motion control.

Handbook of Marine Craft Hydrodynamics and Motion Control [Bookshelf]

1. Introduction 2. Observation techniques 3. Description of ocean waves 4. Statistics 5. Linear wave theory (oceanic waters) 6. Waves in oceanic waters 7. Linear wave theory (coastal waters) 8. Waves in coastal waters 9. The SWAN wave model Appendices References Index.

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Waves in Oceanic and Coastal Waters

SUMMARY
The open-source CFD library OpenFoam® contains a method for solving free surface Newtonian flows using the Reynolds averaged Navier–Stokes equations coupled with a volume of fluid method. In this paper, it is demonstrated how this has been extended with a generic wave generation and absorption method termed ‘wave relaxation zones’, on which a detailed account is given. The ability to use OpenFoam for the modelling of waves is demonstrated using two benchmark test cases, which show the ability to model wave propagation and wave breaking. Furthermore, the reflection coefficient from outlet relaxation zones is considered for a range of parameters. The toolbox is implemented in C++, and the flexibility in deriving new relaxation methods and implementing new wave theories along with other shapes of the relaxation zone is outlined. Subsequent to the publication of this paper, the toolbox has been made freely available through the OpenFoam-Extend Community. Copyright © 2011 John Wiley & Sons, Ltd.

A wave generation toolbox for the open‐source CFD library: OpenFoam®

http://personalpages.to.infn.it/~onorato/publications_files/2013_Onorato_etal_PhysRep.pdf

Rogue waves and their generating mechanisms in different physical contexts

This book is intended as an introduction to classical water wave theory for the college senior or first year graduate student. The material is self-contained; almost all mathematical and engineering concepts are presented or derived in the text, thus making the book accessible to practicing engineers as well.The book commences with a review of fluid mechanics and basic vector concepts. The formulation and solution of the governing boundary value problem for small amplitude waves are developed and the kinematic and pressure fields for short and long waves are explored. The transformation of waves due to variations in depth and their interactions with structures are derived. Wavemaker theories and the statistics of ocean waves are reviewed. The application of the water particle motions and pressure fields are applied to the calculation of wave forces on small and large objects. Extension of the linear theory results to several nonlinear wave properties is presented. Each chapter concludes with a set of homework problems exercising and sometimes extending the material presented in the chapter. An appendix provides a description of nine experiments which can be performed, with little additional equipment, in most wave tank facilities.

Water wave mechanics for engineers and scientists

An understanding of equilibrium beach profiles can be useful in a number of types of coastal engineering projects. Empirical correlations between a scale parameter and the sediment size or fall velocity allow computation of equilibrium beach profiles. The most often used form is h(y) = Ay 2/3 in which h is the water depth at a distance y from the shoreline and A is the sediment-dependent scale parameter. Expressions for shoreline position change are presented for arbitrary water levels and wave heights. Application of equilibrium beach profile concepts to profile changes seaward of a seawall include effects of sea level change and arbitrary wave heights. For fixed wave heights and increasing water level, the additional depth adjacent to the seawall first increases, then decreases to zero for a wave height just breaking at the seawall. Shoreline recession and implications due to increased sea level and wave heights are examined. It is shown, for the equilibrium profile form examined, that the effect of wave set-up on recession is small compared to expected storm tides during storms. Profile evolution from a uniform slope is shown to result in five different profile types, depending on initial slope, sediment characteristics, berm height and depth of active sediment redistribution. The reduction in required sand volumes through perching of a nourished beach by an offshore sill is examined for arbitrary sediment and sill combinations. When beaches are nourished with a sediment of arbitrary but uniform size, it is found that three types of profiles can result: (1) submerged profiles in which the placed sediment is of smaller diameter than the native and all of the sediment equilibrates underwater with no widening of the dry beach, (2) non-intersecting profiles in which the sea- ward portion of the placed material lies above the original profile at that location, and (3) intersecting profiles with the placed sand coarser than the native and resulting in the placed profile intersecting with the original profile. Equations and graphs are presented portraying the additional dry beach width for differing volumes of sand of varying sizes relative to the native. The offshore volumetric redistribution of material due to sea level rise as a function of water depth is of interest in interpreting the cause of shoreline recession. If only offshore transport occurs and the surveys extend over the active profile, the net volumetric change is zero. It is shown that the maximum volume change due to cross-shore sediment redistribution is only a fraction of the product of the active vertical profile dimension and shoreline recession. The paper presents several other applications of equilibrium beach profiles to problems of coastal engineering interest.

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Equilibrium Beach Profiles: Characteristics and Applications

Part I. Introduction to Coastal Processes: 1. Overview 2. Sediment characteristics 3. Long-term processes Part II. Hydrodynamics of the Coastal Zone: 4. Tides and storm surges 5. Waves and wave-induced hydrodynamics Part III. Coastal Response: 6. Field measurement techniques and analysis 7. Equilibrium beach profiles 8. Sediment transport 9. Miscellaneous coastal features 10. Modeling of beaches and shorelines Part IV. Shoreline Modification and Analysis: 11. Beach fill and soft engineering structures 12. Hard engineering structures 13. Tidal inlets 14. Shoreline management.

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Coastal Processes with Engineering Applications

Physical mechanisms are described for both the onshore/offshore and longshore modes of sand transport within the surf zone. The onshore/offshore mode of motion is based on consideration of whether the initial sand suspended during the wave breaking undergoes a net shoreward or seaward displacement as it falls to the bottom. The two important parameters are the wave steepness and ratio of fall velocity to wave period. Using data from three earlier investigators, and choosing one empirical constant, it is found that these two parameters can predict the correct onshore or offshore direction of sand motion in 161 of 184 individual experimental runs. The longshore mode of motion (littoral drift) is considered to be the advection, by the longshore current, of the sand suspended by the breaking waves. The quantity of sand suspended is taken to be an amount which, during its fall to the bottom, consumes a fixed portion of the wave energy flux into the surf zone. The average longshore current is based on the simplest representation by Longuet - Higgins. The resulting expression for littoral drift is quite similar to earlier empirically determined equations; however, the relationship here obtained includes beach slope, sand grain diameter, beach roughness, etc. These models should be useful in beach restoration projects and other coastal engineering projects concerned with sand transport within the surf zone.

Heuristic Models of Sand Transport in the Surf Zone

An intuitive expression for the spatial change in energy flux associated with waves breaking in the surf zone is developed. Using shallow water linear wave theory, analytical solutions for wave height transformation due to shoaling and breaking on a flat shelf, a plane slope, and an “equilibrium” beach profile are derived and then compared to laboratory data with favorable results. The effect of beach slope on wave decay is included explicitly, while wave steepness effects are included implicitly by specification of the incipient conditions. Set-down/set-up in the mean water level, bottom friction losses, and bottom profiles of arbitrary shape are introduced, and solutions are obtained numerically. The model is calibrated and verified using laboratory data with very good results for the wave decay but not so favorable results for set-up. A test run on a prototype scale profile containing two bar and trough systems demonstrates the model's ability to describe the shoaling, breaking, and wave re-forming process commonly observed in nature. Bottom friction is found to play a negligible role in wave decay in the surf zone when compared to shoaling and breaking.

Robert G. Dean

Papers

Water wave mechanics for engineers and scientists

Equilibrium Beach Profiles: Characteristics and Applications

Coastal Processes with Engineering Applications

Heuristic Models of Sand Transport in the Surf Zone

Wave height variation across beaches of arbitrary profile