Robert A. Dalrymple
Other affiliations: University of Delaware, University of Manchester, University of Florida ...read more
Bio: Robert A. Dalrymple is an academic researcher from Johns Hopkins University. The author has contributed to research in topics: Breaking wave & Wave propagation. The author has an hindex of 49, co-authored 265 publications receiving 12684 citations. Previous affiliations of Robert A. Dalrymple include University of Delaware & University of Manchester.
Papers published on a yearly basis
01 Sep 1983
TL;DR: In this paper, the authors present an introduction to classical water wave theory for the college senior or first year graduate student, with a set of homework problems exercising and sometimes extending the material presented in the chapter.
Abstract: 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.
TL;DR: Several improvements that are implemented are presented here to handle turbulence, the fluid viscosity and density, and a different time-stepping algorithm is used.
Abstract: Smoothed Particle Hydrodynamics (SPH) is a relatively new method for examining the propagation of highly nonlinear and breaking waves. At Johns Hopkins University, we have been working since 2000 to develop an engineering tool using this technique. However, there have been some difficulties in taking the model from examples using a small number of particles to more elaborate and better resolved cases. Several improvements that we have implemented are presented here to handle turbulence, the fluid viscosity and density, and a different time-stepping algorithm is used. The final model is shown to be able to model breaking waves on beaches in two and three dimensions, green water overtopping of decks, and wave–structure interaction.
TL;DR: In this article, an extended Boussinesq model for surf zone hydrodynamics in two horizontal dimensions is implemented and verified using an eddy viscosity term.
Abstract: In this paper, we focus on the implementation and verification of an extended Boussinesq model for surf zone hydrodynamics in two horizontal dimensions The time-domain numerical model is based on the fully nonlinear Boussinesq equations As described in Part I of this two-part paper, the energy dissipation due to wave breaking is modeled by introducing an eddy viscosity term into the momentum equations, with the viscosity strongly localized on the front face of the breaking waves Wave runup on the beach is simulated using a permeable-seabed technique We apply the model to simulate two laboratory experiments in large wave basins They are wave transformation and breaking over a submerged circular shoal and solitary wave runup on a conical island Satisfactory agreement is found between the numerical results and the laboratory measurements
•12 Nov 2001
TL;DR: In this article, the authors present an overview of the coastal process and its long-term processes, including longterm processes of sediment transport, flooding, and storm surge, as well as modeling of beaches and shorelines.
Abstract: 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.
TL;DR: In this article, a parabolic model for calculating the combined refraction/diffraction of monochromatic linear waves is developed, including a term which allows for the dissipation of wave energy.
Abstract: A parabolic model for calculating the combined refraction/diffraction of monochromatic linear waves is developed, including a term which allows for the dissipation of wave energy. The coefficient of the dissipation term is related to a number of dissipative models. Wave calculations are performed for a localized area of dissipation, based on a friction model for a spatial distribution of rigid vertical cylinders. The region of localized dissipation creates a shadow region of low wave energy, which may have important implications for the response of neighboring shore lines.
01 Jan 2005
TL;DR: The Monthly Notices as mentioned in this paper is one of the three largest general primary astronomical research publications in the world, published by the Royal Astronomical Society (RAE), and it is the most widely cited journal in astronomy.
Abstract: Monthly Notices is one of the three largest general primary astronomical research publications. It is an international journal, published by the Royal Astronomical Society. This article 1 describes its publication policy and practice.
TL;DR: In this paper, a synthesis of some results obtained over the period 1979-1982 from a study of beach and surf zone dynamics is presented, dealing with the different natural beach states, the process signatures associated with these states, environmental controls on modal beach state, and the temporal variability of beach state and beach profiles.
Abstract: A synthesis of some results obtained over the period 1979–1982 from a study of beach and surf zone dynamics is presented. The paper deals with the different natural beach states, the process signatures associated with these states, environmental controls on modal beach state, and the temporal variability of beach state and beach profiles. Hydrodynamic processes and the relative contributions of different mechanisms to sediment transport and morphologic change differ dramatically as functions of beach state, that is depending on whether the surf zone and beach are reflective, dissipative or in one of several intermediate states. Depending on beach state, near bottom currents show variations in the relative dominance of motions due to: incident waves, subharmonic oscillations, infragravity oscillations, and mean longshore and rip currents. On reflective beaches, incident waves and subharmonic edge waves are dominant. In highly dissipative surf zones, shoreward decay of incident waves is accompanied by shoreward growth of infragravity energy; in the inner surf zone, currents associated with infragravity standing waves dominate. On intermediate states with pronounced bar-trough (straight or crescentic) topographies, incident wave orbital velocities are generally dominant but significant roles are also played by subharmonic and infragravity standing waves, longshore currents, and rips. The strongest rips and associated feeder currents occur in association with intermediate transverse bar and rip topographies. Long-term consecutive surveys of different beaches with contrasting local environmental conditions provide the data sets for empirical—statistical assessment of beach mobility, direction of change and response to environmental conditions. Conditions of persistently high wave energy combined with abundant and/or fine grained sediment results in maintaining highly dissipative states which exhibit very low mobility. Relatively low mobility is also associated with persistently low-steepness waves acting on coarsegrained beach sediments. In such cases, the modal beach state is reflective. The greatest degree of mobility is associated with intermediate but highly changeable wave conditions, medium grained sediment and a modest or meager sediment supply. Under such conditions, the beach and surf zone tend to alternate among the intermediate states and to exhibit well-developed bar trough and rhythmic topographies. A good association is found between beach state and the environmental parameter Ω = H b ( w s T ) where Hb is breaker height, w s is mean sediment fall velocity and T is wave period. Temporal variability of beach state reflects, in part, the temporal variability and rate of change of Ω, which, in turn depends on deep-water wave climate and nearshore wave modifications.
TL;DR: An overview on the SPH method and its recent developments is presented, including the need for meshfree particle methods, and advantages of SPH, and several important numerical aspects.
Abstract: Smoothed particle hydrodynamics (SPH) is a meshfree particle method based on Lagrangian formulation, and has been widely applied to different areas in engineering and science. This paper presents an overview on the SPH method and its recent developments, including (1) the need for meshfree particle methods, and advantages of SPH, (2) approximation schemes of the conventional SPH method and numerical techniques for deriving SPH formulations for partial differential equations such as the Navier-Stokes (N-S) equations, (3) the role of the smoothing kernel functions and a general approach to construct smoothing kernel functions, (4) kernel and particle consistency for the SPH method, and approaches for restoring particle consistency, (5) several important numerical aspects, and (6) some recent applications of SPH. The paper ends with some concluding remarks.
01 Jan 2014
TL;DR: Fossen as discussed by the authors provides a comprehensive manuscript encompassing two separable texts on hydrodynamics and control of marine vehicles, including a detailed treatment of the subject matter, written from a more generalist perspective.
Abstract: 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.