bluuebunny/crossref_metadata_2025 huggingface dataset:
LIFE OF STEEL SHEET PILE STRUCTURES IN ATLANTIC COASTAL STATES
Authors: Rayner Albert C.
Published: June 2017

As a basis for more accurate estimates of the useful life of steel sheet piling, in 1936 the Beach Erosion Board, in cooperation with a number of District offices of the Corps of Engineers, began a survey of the rate of deterioration of steel sheet piling. The plan of operations was developed by and the first inspection was made under the supervision of Mr. Ralph F. Rhodes, Engineer of the Savannah District. Subsequent inspections were under the supervision of Mr. Jay V. Hall, Jr. and most of the compilation and analysis of data were done by Mr. C. W. Ross, both of the Beach Erosion Board staff. The Corps of Engineers is indebted to the many owners of structures who contributed to the study by permitting drilling and measurement of piling.
CIRCULATION IN ESTUARIES
Authors: Ketchum Bostwick H.
Published: June 2017

In discussing the circulation in estuaries, an apparent paradox must always be kept in mind. In the first place the problems of estuarine circulation are unique, being different from the problems of the open sea, and from the problems of river hydrology. Estuarine circulation and related problems consequently constitute a valid field for investigation. In contrast to this viewpoint is the tremendous range of conditions found in various estuaries - no two are alike. This inherent variability of estuaries discourages generalizations about the circulation.
ENSEMBLE FORECAST OF EXTREME STORM SURGE: A CASE STUDY OF 2013 TYPHOON HAIYAN
Authors: Nakamura Ryota , Shibayama Tomoya
Published: June 2017

The object of this study is to evaluate an ensemble forecast of extreme storm surge by using a case of Typhoon Haiyan (2013) and its associated storm surge. A simple numerical model composed of ARW-WRF, FVCOM and SWAN is employed as a forecast system for storm surge. This ensemble system can successfully forecast storm surge 3-4 days before it happened. However, the typhoons in almost all ensemble members were underpredicted probably because of its difficulty in forecasting a track and central pressure of highly intense typhoon. This leads to the underestimation of a prediction of storm surges around Leyte Gulf. Compensating the underestimation of forecasted extreme storm surge, it can be important to not only examine the ensemble mean among members but also consider the phase-shifted manipulation and the worst ensemble member in the case where the extreme storm surge is forecasted. In addition, the ensemble forecast system can have a potential to determine the time at which the peak of extreme surge appears with a high precision.
APPLICATION OF SMOOTHED PARTICLE HYDRODYNAMICS (SPH) IN NEARSHORE MIXING: A COMPARISON TO LABORATORY DATA
Authors: Abolfathi Soroush , Pearson Jonathan
Published: June 2017

A weakly compressible smoothed particle hydrodynamics (WCSPH) method is used to simulate the nearshore flow hydrodynamics. The wave induced dispersion and diffusion are determined for monochromatic waves with significant wave height of 0.12 m and the wave period of 1.2 sec (Sop=5%) based on WCSPH wave dynamics. The hydrodynamics of WCSPH model are compared to the laboratory results obtained from series of LDA measurements. The overall mixing coefficients across the nearshore are determined from WCSPH hydrodynamics. The mixing coefficients obtained are compared with the values determined from a series of fluorometric studies performed in a large-scale facility in DHI, Denmark. The results show that the wave profiles are in good agreement with the experimental data. The WCSPH model is proven to be well capable of estimating the dispersion across the nearshore.
SWASH MODELLING OF A COASTAL PROTECTION SCHEME
Authors: Klein Mark , Symonds Andrew , Zijlema Marcel , Messiter Dan , Dufour Michael
Published: June 2017

The Beresford shoreline, Australia, is subject to a complex interaction of coastal processes and associated erosion. In support of the design of a coastal protection scheme a SWASH model has been set up capable of accounting for all the complex processes at hand. The model has successfully been validated against measured wave and current conditions. In the design process the validated SWASH model proved to be a valuable tool to assess the impact of various coastal protection schemes like groynes on the wave-driven current patterns and associated sediment pathways.
WAVE SETUP ON VEGETATED BEACH: LABORATORY EXPERIMENTS
Authors: Ozeren Yavuz , Wren Daniel , Wu Weiming
Published: June 2017

In this study, wave height evolution and wave setup were measured in a laboratory wave tank with a sloping beach covered with rigid and flexible artificial vegetation under regular and irregular wave conditions. The experiments were conducted in a 20.6 m long, 0.69 m wide and 1.22 m deep wave tank at the USDA-ARS National Sedimentation Laboratory, Oxford, MS, USA. Regular and irregular waves were generated using a computer controlled piston type wave generator. A plane wooden beach with a 1:21 slope was constructed at the down-wave end of the wave tank, 11.5 m away from the wave paddle. Rigid vegetation was constructed out of wooden dowels and flexible vegetation was constructed using polyurethane tubes. Both vegetation models were 3.1 mm in diameter and 0.2 m long and had a population density of 3,182 stems/m2. The results were compared with those from experiments on a non-vegetated plane beach. Both rigid and flexible vegetation models reduced the wave height and wave setup substantially, but rigid vegetation typically performed better in reducing wave setup. For some of the experiments, no wave breaking was observed over the vegetated models, indicating that wave attenuation due to vegetation reduced the shoaling rate. For other experiments, wave breaking was observed and wave height attenuation was very small; however, wave setup was still significantly lower than in the plane beach experiments.
INTER-COMPARISON OF RECENT TIDE MODELS FOR THE PERSIAN GULF AND OMAN SEA
Authors: Ranji Zahra , Hejazi Kourosh , Soltanpour Mohsen , Allahyar Mohammad Reza
Published: June 2017

Using several series of field measurements data along Iranian coastline of the Persian Gulf and Gulf of Oman, eight different tide models have been evaluated in this study. By comparing the results in the frequency domain, it was found that the model discrepancies arise in shallow waters, having maximum error in the shallowest part of the Persian Gulf, where Pohl station is located. On the other hand, maximum error of tide models is limited to 10 cm in deeper part of the Persian Gulf, indicating that different tide models result in close outcome in deeper waters. Considering the results in the time domain, it was found that FES model, which includes more shallow water constituents, results in better tidal level predictions. FES also presents the best tidal current predictions in the area of the interest of this study.
FOREWORD: Proceedings of the 35th International Conference
Authors: Lynett Patrick J.
Published: June 2017

This Proceedings contains 170 papers from the 35th International Conference on Coastal Engineering, which was held in Antalya, Turkey from November 17 to November 20, 2016. The Proceedings is divided into six parts: Waves; Swash, Nearshore Currents, and Long Waves; Sediment Transport and Morphology; Coastal Structures; Coastal Management, Environment, and Risk, and Posters. The individual papers cover a broad range of topics including theory, numerical and physical modeling, field measurements, case studies, design, and management. These papers provide engineers, scientists, and planners state-of-the-art information on coastal engineering and coastal processes.
EXCITATION AND DYNAMIC RESPONSES OF JACKET STRUCTURES IN REGULAR WAVES FOR OFFSHORE INSTALLATION
Authors: Welzel Mario , Kreklow Tobias , Schlurmann Torsten , Hildebrandt Arndt
Published: June 2017

The worldâ€™s energy supply needs to scope two aims: Securing an ongoing growth in energy demand while gradually shifting to exploitation of renewable energy resources. Since onshore and near shore areas to harvest energy from wind are running short, the focus is laid on concepts for deep water regions ranging from 30 up to 50m with over 6MW. The presented work is a part of the research project HyConCast which progresses the development of a novel, hybrid support structure for offshore wind turbines. Thereby the concept addresses to develop and deploy hybrid offshore wind farm support structures which are based on the advantages of combined ductile iron casting knots and precast concrete pipes. The overall objective of the project is to assess the feasibility and general applicability under design load cases stemming from environmental, eco-logical and economical dimensions. With respect to the distinctly higher total weight of the hybrid structure compared to common steal structures, the results of its so far not understood excitation and dynamic motion response in regular waves during floating installation are researched and discussed in the following article.
COASTAL EROSION TRIGGERED BY POLITICAL AND SOCIO-ECONOMICAL ABRUPT CHANGES: THE CASE OF LALZIT BAY, ALBANIA
Authors: De Leo Francesco , Besio Giovanni , Zolezzi Guido , Bezzi Marco , Floqi Tania , Lami Idlir
Published: June 2017

Countries that undergo abrupt changes in their political regimes, such as the transition from totalitarianism to systems

based on democratic principles, experience socio-economic changes that may also have a direct impact on the trans-

formation and the anthropic pressure applied to the environment. This can ranges from the scale of small communities

to larger spatial scales, such as that of a catchment basin. The rise of a liberal society in countries such as the Eastern

European nations, often lacks a structure capable of regulating and planning the development of the territory and the

use of natural resources, which should be aimed at conciliating the new development needs with the sustainable man-

agement of the environment. This paper describes and analyses the extensive coastal erosion that has taken place over

the past thirty years in Lalzit Bay, Albania, which may be attributed to the great social and economic transformations

that occurred in the country after the fall of Enver Hoxaâ€™s communist regime in 1991, and the consequent changes in

land use. These led to a significant reduction in the volume of sediment carried by rivers, which was necessary for the

morphological equilibrium of the coast and its natural replenishment.
EXPERIMENTAL INVESTIGATIONS ON FULL DEPTH BUOYANCY FLOWS IN THE PRESENCEOF SURFACE WAVES
Authors: Musumeci Rosaria Ester , Stancanelli Laura Maria , Foti Enrico
Published: June 2017

The propagation of density currents in the presence of waves is experimentally investigated by considering a lock exchange schematization. In particular, we perform experiments considering the classical lock release, where the only driving force is buoyancy, as well as lock-exchange experiments with superimposed periodic surface waves, where the driving forces are both buoyancy and the wave-induced orbital motion. The application of an image processing technique is used for the detection of the main features of the front propagation (i.e depth, height, velocity etc.). All experiments are in full-depth conditions. The propagation of the waves is in intermediate water depth conditions. The presence of surface waves induces an orbital motion along the water column able to modify the dynamics of the density current propagation. Results show that the oscillation of the front advancement, as well as the oscillation of the gravity current depth observed in the presence of waves, are directly correlated with the wave period.
FRAGILITY OF FLOATING DOCKS FOR SMALL CRAFT MARINAS
Authors: Keen Adam Steven , Lynett Patrick , Eskijian Martin , AyÃ§a Aykut
Published: June 2017

As a result of damage from the 2010 Chile and 2011 Japanese teletsunamis, the tsunami risk to the small craft marinas in California has become an important concern. This paper outlines an assessment tool which can be used to assess the tsunami hazard to small craft harbors. The methodology is based on the demand and capacity of a floating dock system. Results are provided as fragility curves and give a quantitative assessment of survivability. This tool is not exact and is provided only to give an indication as to survivability and/or failure of a floating dock system of vessels and floating components/piles, subject to tsunami events. The purpose is to quickly evaluate whether or not a floating dock is likely to survive or be destroyed by a tsunami having the input properties.
MODELLING LONG-TERM SHORELINE EVOLUTION: FIGUEIRA DA FOZ BEACH, PORTUGAL
Authors: Pereira Carla , Coelho Carlos , Silva Paulo A.
Published: June 2017

This work applies two different shoreline evolution numerical models (LTC and GENESIS) in two different time periods (1980 2010 and 2010-2014) to compare respectively the calibration and validation performance of the models. The models were applied to evaluate long-term shoreline position and longshore sediments transport evolution, considering as a case study a sandy beach stretch located updrift of the Figueira da Foz harbor jetty, on the Northwest Portuguese coast. Due to the jetty extension, this stretch exhibits a clear accretion trend during the analyzed time periods. For this region, the longshore sediment transport rate estimated by several authors varies between 200 and 1500x103m3/year. According to the modelling results, it was observed that both models reproduce reasonably well the shoreline evolution between 1980 and 2010. In average, the LTC model reproduces a 2010 shoreline position nearest the observed and GENESIS presents better approximation in the Northern part of the beach and also near the South (downdrift) border (just close to the Northern jetty of the harbor). The modeled shoreline average accretion rates for the considered stretch is quite similar and close to the values referred in the bibliography, which indicates that the beach presents 500 meters of maximum accretion width updrift the jetty (about 16.6m/year). In what concerns to the longshore sediment transport it was observed that numerical models generally indicate lower values than the bibliography, being GENESIS results higher and closer to the observed than the LTC. These results are common in the numerical modelling of shoreline evolution, showing that is difficult to simultaneously represent both the shoreline position and sediment transport volumes. After calibration, LTC validation was evaluated for the time period between 2010 and 2014 to allow confidence in the extrapolation of results to the future. Estimated deposition rates of about 350x103m3/year were obtained at the harbor entrance.
SUSPENDED AND BEDLOAD TRANSPORT IN THE SURF ZONE: IMPLICATIONS FOR SAND TRANSPORT MODELS
Authors: Zanden Joep van der , Van der A Dominic A. , O'Donoghue Tom , Hurther David , Caceres Ivan , Thorne Peter D. , Van der Werf Jebbe J. , Hulscher Suzanne J.M.H. , Ribberink Jan S.
Published: June 2017

This paper presents results obtained during a large-scale wave flume experiment focused at measuring hydrodynamics and sediment transport processes in the wave breaking region. The experiment involved monochromatic plunging breaking waves over a mobile bed barred profile consisting of D50 = 0.24 mm sand. Vertical profiles of velocity, turbulence, sand concentration and sand fluxes were measured at 12 cross-shore locations, covering the shoaling region up to the inner surf zone. Particularly high-resolution profiles were obtained near the bed within the wave bottom boundary layer, using an acoustic sediment concentration and velocity profiler (ACVP). Sheet flow concentration and particle velocities were measured at two locations near the bar crest using two conductivity-based concentration measurement tanks (CCM+). Total transport rates, obtained from the evolving bed profile measurements, were decomposed into suspended and bedload transport contributions across the bar. The present paper presents a summary of the key findings of the experiment, which are used to discuss existing approaches for modeling suspended and bed load transport in the surf zone.
COMPARISON OF ROCK SEAWALL AND DUNE FOR STORM DAMAGE REDUCTION
Authors: Kim Hyun Dong , Kobayashi Nobuhisa , Cardenas Xavier Chavez
Published: June 2017

Four test series consisting of 14 tests and 140 runs (each run lasted 400 s) were conducted in a wave flume with a sand beach and a berm in order to compare the effectiveness of a dune and a rock (stone) seawall placed on the foreshore in reducing wave overtopping and sand overwash. The incident irregular waves were kept approximately the same for all the runs. The water level was increased to create dune erosion and crest lowering as well as stone displacement. The dune was effective in eliminating or reducing wave overtopping and overwash in comparison to the corresponding berm with no dune but the narrow dune was destroyed easily as the water level was increased. The stone seawall reduced wave overtopping and overwash even after it was damaged moderately. A stone seawall buried inside a dune was examined in the last test series. The buried seawall functioned like the dune initially and like the seawall after the sand on the seawall was eroded by overtopping waves. The buried seawall combines the aesthetics of the dune and the robustness of the stone seawall.
VERIFICATION OF THE CROWN WALL STABILITY TAKING INTO ACCOUNT THE HYDRAULIC PERFORMANCE CURVES
Authors: VÃ­lchez Montse , DÃ­az-Carrasco Pilar , Clavero MarÃ­a , Ortega-SÃ¡nchez Miguel , Losada Miguel A.
Published: June 2017

The design of a breakwater requires that the failure modes which can affect its security, functionality and operationality

in its useful life are bounded. The failure modes can be verified by means of the corresponding verification equation.

In this work, a unified methodology to verify simultaneously the failure modes produce by wind waves in front or

face of the breakwater is presented. This methodology is based on formulate the verification equations of the failure

modes forced by wind waves in the front or face of the breakwater in terms of the kinematic and dynamic variables

of the flow at these locations. It has been applied to analyse the failure mode that considers sliding of the crown wall.

Results show that the parameters of the pdf of these variables depend on the total wave height at the same location and

therefore, the verification equation can be also formulated in terms of this variable.
NUMERICAL STUDY OF WAVE RUN-UP AT PERMEABLE FIXED REVETMENT SLOPE
Authors: Kantarzhi Izmail , Kivva Sergii , Shunko Natalia V
Published: June 2017

The numerical model of wave surface elevation and water filtration in the saturated-unsaturated porous medium is developed. The model uses to define the parameters of the wave run-up at the slope protected by the permeable fixed layer. The model shows the wave surface in the different times, including the wave run-up height at the slope and wave run-down. Also, the velocities in the upper protected layer as well in the soil body of the slope are defined. Model is verified with using of the published large-scale tests with the slopes protected by Elastocoast technology layers. The tests were carried out in the wave flume of Technical University Braunschweig. The numerical model may be applied to calculate the maximal waves run-up at the protected engineering and beach slopes in natural conditions.
UPDATE OF THE EUROTOP MANUAL: NEW INSIGHTS ON WAVE OVERTOPPING
Authors: Van der Meer Jentsje W. , Allsop William , Bruce Tom , De Rouck Julien , Pullen Tim , Schuttrumph Holger , Troch Peter , Zanuttigh Barbara
Published: June 2017

Quite some new insights on wave overtopping were achieved since the first submission of the EurOtop Manual in 2007, which have now resulted in a second edition of this Manual. A major improvement has been made on the understanding of wave by wave overtopping and tolerable wave overtopping that is connected to it. Many videos are available on the overtopping website that show all kind of overtopping discharges and volumes and may give guidance for the user of the Manual. The EurOtop Neural Network and the EurOtop database are improved and extended versions of the earlier NN and CLASH database. New insights and prediction formulae have been developed for very low freeboards; for very steep slopes up to vertical walls; for run-up on steep slopes; for overtopping on storm walls on a promenade; and for overtopping on vertical walls, where overtopping has been divided in situations with and without an influencing foreshore and where the first situation may be divided in non-impulsive and impulsive overtopping.
ROCK SLOPES WITH OPEN FILTERS UNDER WAVE LOADING: EFFECTS OF STORM DURATION AND WATER LEVEL VARIATIONS
Authors: Van Gent Marcel R.A. , Wolters Guido , Van der Werf Ivo M.
Published: June 2017

Rubble mound breakwaters and revetments typically contain granular filters in one or more layers. The transition from the armour layer to the filter layer, and transitions between other layers within the structure, are normally geometrically tight to prevent material washout. This requires a limited ratio of the material size of the upper layer and neighbouring layer. An alternative is a geometrically open filter where in principle underlayer material can be transported into the upper layer, but if the hydraulic load at this transition between two layers remains low, the transition can be designed such that no or limited transport occurs, see for instance Van Gent and Wolters (2015), Van Gent et al (2015) and Jacobsen et al, (2017). This allows for larger ratios of material sizes, which can reduce the number of filter layers, and relax the material requirements with respect to the width of gradings. This can lead to considerable cost savings. In Van Gent and Wolters (2015) physical model tests for the transition between a layer of rock and an underlayer that consists of sand have been performed and design guidelines have been derived. Here, additional physical model tests are presented to study the influence of the storm duration and water level variations on the response of sand underneath a layer of rock.
SPECTRAL PARTITIONING AND SWELLS IN THE BLACK SEA
Authors: Vledder Gerbrant van , Akpinar Adem
Published: June 2017

The swell climate of the Black Sea has been determined using a long-term 31-year wave hindcast with the third-generation spectral wave model SWAN in combination with spectral partitioning. This technique enables decomposing wave spectra into individual wave systems representing wind seas or swells and computing integral wave parameters of each partition. Results are presented of the partition technique and of spatial and seasonal characteristics of wind sea and swell systems. In addition, the average amount of swell energy and the occurrence probability of dangerous crossing sea states are determined.
THREE-LAYER ANALYTICAL SOLUTION FOR WAVE ATTENUATION BY SUSPENDED AND NONSUSPENDED VEGETATION CANOPY
Authors: Zhu Longhuan , Zou Qingping
Published: June 2017

A generalized three-layer analytical solution for the wave attenuation by suspended and non-suspended vegetation canopy is developed in this study. The analytical solution reduces to the two-layer analytical solution by Kobayashi et al. (1993) for the non-suspended vegetation canopy rooted at the sea bed. The present theory is verified using laboratory experiments and field observations of a suspended and non-suspended as well as emerged and submerged vegetation canopy. The wave attenuation increase with the drag coefficient, blade diameter and length, canopy density and length, the elevation of the bottom of the canopy and the incident wave height. The influences of wave frequency and water depth on wave attenuation are more complex. They affect the wave attenuation mainly by changing the wave flow velocity encountered by the vegetation canopy. As a result, the canopy vertical position has significant impact on the relationship between the wave attenuation and wave frequency.
FLOW DYNAMICS OF WAVES PROPAGATING OVER DIFFERENT PERMEABLE BEDS
Authors: Corvaro Sara , Mancinelli Alessandro , Brocchini Maurizio
Published: June 2017

The analysis of the hydrodynamics over porous media is of interest for many coastal engineering applications as the wave propagation over permeable structures or gravel beaches. The study of a boundary layer evolving over permeable beds is important to a better understanding of the interactions between the flow over and inside the porous medium. An experimental study has been performed to analyze the dynamics produced when waves propagate over two kinds of permeable beds: spheres (regular permeability) and natural stones. For comparative purposes the same analysis has been extended to two rough beds made, respectively, by a single layer of spheres and natural stones. We here focus on the correlation between the wave energy reduction induced by a porous bed and the flow resistance. An experimental law for the prediction of the friction factor is found by using the log-fit method in analogy to that reported in Dixen et al. (2008) for rough beds. Moreover, inspection of the turbulent velocity components allows one to evaluate the bottom shear stress. The latter analysis has been performed for different permeable beds (regular and irregular beds). A good agreement between the bottom shear stress behavior and the wave height attenuation over rough and permeable beds (Corvaro et al. 2010 and Corvaro et al. 2014a) has been observed.
WAVE ENERGY RESOURCES ALONG CALABRIAN COASTS (ITALY)
Authors: Algieri Ferraro Danilo , Aristodemo Francesco , Veltri Paolo
Published: June 2017

The assessment of wave energy is fundamental to well evaluate potential wave energy at different sea locations and time scales in conjunction with the related occurrence of hot spots for an optimal installation of Wave Energy Converters (WECs). The present study has been performed off the coasts of Calabria (Southern Italy), a Mediterranean region characterized by a mild wave climate and quite representative of mean sea states in the Mediterranean basin. The wave energy potential has been assessed in deep waters by means of ECMWF operational wave data validated against RON buoys and UKMO data. The wave power is calculated as a function of the energy wave period deduced from directional wave spectra and compared with widely adopted relationships based on the use of a standard JONSWAP spectrum. The mean yearly and seasonal wave energy is then assessed at selected hot spots for Tyrrhenian and Ionian Seas at a water deep of 100 m suitable for the installation of several offshore WECs.
PRINCIPLES OF SHORE PROTECTION FOR THE GREAT LAKES
Authors: Mason Martin A.
Published: June 2017

The Great Lakes region is one of quiet challenge and absorbing interest to the coastal engineer. From the broad pattern of its morphologic history to the detail of its present-day shoreline it presents a fascinating variety of natural phenomena and man-imposed regimen that has controlled and still conditions its shoreline behavior. Many of the features of the behavior pattern and its controls are recognized and subject to beneficial management) some of these are either not recognized or are ignored by coastal experts who should know better; while others are as yet beyond the capabilities of the methods of beneficial management available today.
STATISTICAL PROBLEMS OF SAMPLE SIZE AND SPACING ON LAKE MICHIGAN BEACHES
Authors: Krumbein W. C.
Published: June 2017

Beaches along Lake Michigan display a wide range in texture and composition. Some are composed of fairly uniform sand or gravel, others display an irregular mixture of both. Host beach sand is predominantly quartz with variable amounts of calcite, feldspar, and heavy minerals. Some gravel beaches are composed wholly of limestone or dolomite pebbles of local origin; in others the pebbles have the varied composition of their parent glacial materials.
THE HAVRE LABORATORY FOR MEASURING THE FORCE OF WAVES
Authors: Cot Pierre D.
Published: June 2017

The International Committee for studying the force of waves, a Committee set up by the International Association of Navigation Congresses, the activities of which were interrupted by the War, was reconstituted in 1950.

The Le Havre station was built on the Northern breakwater of the Port of Havre in 1949-1950 after an investigation concerning procedures to be used for recording pressure oaused by waves.

The system adopted utilizes variable electric capacities. A manometric membrane made of glucinium bronze, with a diameter of 30 mm (l-J"), carries with it when moving one armature of a condenser, the other armature of which remains stationary. The capacity variations thus introduced into an oscillating circuit with fixed frequency, controlled by quart, are translated into tension variations. The advantages of such a system are good stability and almost complete absence of distortion within the limits of use.
THE SIMILITUDE OF SCALE MODELS FOR THE STUDY OF SEICHES IN HARBOURS
Authors: Biesel F.
Published: June 2017

The study of seiches in harbours is a relatively new scale model technique and poses many problems of similitude. We do not attempt here to be complete and consider all the questions that it poses, nor even to give a detailed account of the studies that the NEYRPIC LABORATORY is now carrying out on this subject. Our purpose is simply to set forth the conclusions that we consider have already been reached and the principal rules of similitude resulting from them. We hope thus to encourage as wide an exchange of opinion as possible
IMPROVEMENTS IN THE ELECTRIC STEP GAUGE FOR MEASURING WAVE HEIGHTS
Authors: Verhagen C. M.
Published: June 2017

Continuous systems are compared with a step system. The influences of parasitic series and coupling resistances are examined. Methods of decreasing these parasitic resistances are considered. Relays are being used to eliminate the errors of these effects. When no relays are used a decrease in the effect of the parasitic resistances is obtained by switching in condensers or inductors instead of resistors in an LC system as part of an oscillator circuit. Some considerations on design are given.
LABORATORY FACILITIES FOR STUDYING WATER GRAVITY WAVE PHENOMENA
Authors: Snyder C. M. , Wiegel R. L. , Bermel K. J.
Published: June 2017

Details are given of the design of laboratory facilities at the University of California for studying water gravity wave phenomena.
TIDAL CURRENTS IN CONSTRICTED INLETS
Authors: Baines W. Douglas
Published: June 2017

Many inlets along the coastline of North America are deep, wide bays which are connected to the ocean by a short channel of much smaller cross-section. Figure 1 is a schematic sketch of such an inlet. It is usual in these inlets that the tide curve (water surface elevation vs. time) in the bay does not coincide with that in the ocean. The range of variation is discussed by Caldwell (1) in a review of inlets in the United States. In addition, Caldwell classifies this type of inlet as one with an inadequate entrance. This term describes well the engineering problem encountered in most of them. There are high velocities in the entrance channel, usually near periods of slack water, which are inconvenient to navigation. In some instances these velocities combined with local geography constitute a serious hazard to shipping.
MODEL INVESTIGATION ON WAVE RUN-UP CARRIED OUT IN THE NETHERLANDS DURING THE PAST TWENTY YEARS
Authors: Wassing F.
Published: June 2017

This paper gives a summary of the results of the model studies on wave run-up carried out in the Netherlands since 1936. More detailed information on these studies is to be found in publication H.L.D. No. 11 to be issued shortly by the Delft Hydraulics Laboratory.
CORRELATION OF WATER LEVEL VARIATIONS WITH WAVE FORCES ON A VERTICAL PILE FOR NONPERIODIC WAVES
Authors: Reid Robert O.
Published: June 2017

This paper describes the design and application of numerical transforms for the estimation of the field of motion associated with irregular, nonperiodic surface waves from measured serial sequences of water level at a fixed point. The design of these transforms is based upon the linear theory for long-crested waves. The method is applied in the analysis of wave forces exerted upon a vertical circular cylinder, where the measured reaction is considered to be expressible as a linear combination of two independent functions of time. One of these functions depends (nonlinearly) upon the velocity field, the other depends (linearly) upon the acceleration field. The covariance of these functions with the measured reaction allows a direct means of evaluation of the drag and inertial coefficients for the cylinder.
WHAT WE ARE DOING ABOUT SEISMIC SEA WAVES
Authors: Karo H. Arnold
Published: June 2017

I am glad to have this opportunity to participate in this section of the Sixth Conference on Coastal Engineering. My remarks to the distinguished group of engineers and scientists assembled here today will emphasize a phase of the work of the Coast and Geodetic Survey of the United States Department of Commerce pertinent to one of the problems encountered in coastal engineering.
Complete Proceedings - Single PDF Download
Authors: Johnson J. W.
Published: June 2017

This conference was sponsored jointly by the Council on Wave Research, Berkeley, California, and the Rijkswaterstaat, of the Netherlands. Dean Morrough P. O'Brien is Chairman of the Council on Wave Research and Mr. A. G Maris is Director - General of the Rijkswaterstaat. Mr. J B Schijf, Chief Engineer-Director of the Rijkswaterstaat, acted as secretary of the conference. Appreciation is expressed to the Rijkswaterstaat for photographs supplied to illustrate the cover and the section title pages of this publication.
ESSAI D'ANALYSE DES PHENOMENES INTERVENANT DANS LA FORMATION D'UN ESTUAIRE
Authors: Banal M.
Published: June 2017

Les considerations qui vont Stre developpe"es re"sultent des observations, des Etudes, et des lectures que l'auteur a pu faire pendant qu*il e"tait charge du Service des acces au port de Rouen sur le fleuve Seine au nord-ouest de la France.

II en resulte que d*une part elles ne valent que pour les estuaires possedant avec celui de la Seine les caracte"ristiques communes qui seront definies ci-dessous, mais d'autre part qu'on s'est efforce d*en exclure ce qui est apparu comme trop particulier au cas de la Seine.

Les conditions auxquelles doit satisfaire un estuaire pour qu*on puisse lui appliquer les considerations qui suivent, sont: - forte maree et faible de~bit fluvial, - embouchure embarrassee de bancs de"couvrants constitue's par du sable fin ou tres fin (granulometrie voisine de 1/10 de mm).
ETUDE SUR MODELE DU TRANSPORT LITTORAL CONDITIONS DE SIMILITUDE
Authors: Valembois J.
Published: June 2017

L*objet do la pr^sente note est d*e"tudier les conditions'de similitude que l'on obtient, pour la representation sur modele du transport littoral, a partir de divers criteres, Les re"sultats concernent les plages form^es de sable fin, a 1*exclusion des plages de galets et des zones ou la vase existe en proportions importantes.

Le premier critere examine" est la reproduction du debut d* entratnement des mate'riaux de fond sous 1' action du mouvement oscillatoire de 1'eau dft a la houle, la oouche limite etant suppos^e laminair* dans la nature et sur lemodele.

Les re"sultats obtenus sont ensuite etendus h la representation du de*but d* entraliiement sous l1action du courant de transport de masse perpendiculaire a la plage, ffifene lorsque cet ecoulement est turbulent au voisinage du fond. La representation correcte du debut d* entratnement conduit probablement a une bonne concordance entre le modele et la nature pour la zone situe"e Men au large du de"ferlement, mais il n'est pas du tout Evident (et il serait m&me etonnant) qu'elle permette d'obtenir sur le modele un transport littoral ressemblant au transport naturel dans les zones voisin.es du deferlement et pres du rivage. En effet, les phenomenes hydrauliques sont tout a fait differents dans ces regions, ou interviennent de facon preponderante la turbulence cr^ee par le deferlement, les courants de masse perpendiculaires et paralleles a la cdte, et probablement la percolation dans la zone de l'estran, ainsi que1*action du vent sur la surface de l'eau.

Pour aller un peu plus loin, on a essaye de definir les conditions dans lesquelles le mouvement des materiaux en suspension est correctement represente sur le modele.

La connaissance incomplete oue l'on a actuellement des lois du transport littoral ne permet pas de decider a priori si les criteres retenus sont valablesj cependant, on est arrive dans divers Laboratoires, avec des modeles dont les echelles etaient voisines de celles auxquelles on aboutirait de cette facon, a representer des transports littoraux assez semblables a ceux de la nature. On verra d'ailleurs que les conditions auxquelles on arrive laissent quelque liberte dans le choix des echelles. Cette liberte a probablement ete utilisee dans le bon sens sur les modeles en question.
SCALE EFFECTS IN MODELS WITH LITTORAL SAND-DRIFT
Authors: Reinalda R.
Published: June 2017

In the "De Voorst" Laboratory of the Hydraulics Laboratory, Delft, a model investigation has been carried out concerning the problems which present themselves around the Thyborjzfa Channel on the west coast of Denmark. This investigation was commissioned by the Danish Board of Maritime Works, who also supplied, the necessary data and information. In tiiis model a scale effect very clearly presented itself with regard to the littoral drift caused by waves, which led to phenomena m the model which deviated considerably from those in the prototype. As this scale effect is likely to occur in some degree in most of the models with littoral drift caused by waves, the publication of the phenomenon observed seems justified.
ESTUARINE CURRENTS AND TIDAL STREAMS
Authors: Agnew Roderick
Published: June 2017

Fresh water spreading out from the mouth of a river as it enters a salt sea may preserve its identity for a considerable distance on the surface if wind-generated waves, longshore currents and tidal streams are capable of producing only weak mixing. Fig. 1 shows the three dimensional shape of a fresh-water tongue overlying more dense salt water, derived by Takano (1954) on the assumption of constant eddy viscosity and constant density in the fresh water layer, below which the density increases according to an assumed law, making an asymptotic approach to the density of salt water. Takano's model is thus a water jet entraining salt from around and below it.

Salt or brackish water may penetrate along the deep channels of an estuary in the shape of a wedge complementary to the fresh water tongue, the salt wedge retreating seawards as heavy rainfall increases the river discharge, and advancing in dry weather intervals. Tidal streams cause a regular oscillation of both fresh and braok water in flood and ebb directions but the seasonal movements of the sloping boundary between fresh and salt water may still be important in low-lying delta regions. Strong tidal streams lead to intense mixing, when neither a fresh water tongue nor a salt wedge can be distinguished, but the isohalines (salinity contours) preserve the general wedge pattern - see Figs. 3 to 6. In the upper reaches of an estuary it is possible to study the effect of the tidal motion by treating it as a simple harmonic perturbation of the uni-directional river flow. Even in the middle portion of the estuary where there is reversal of the horizontal motion, one may seek a "quasi steady" solution for the net effect (seaward movement of fresh water) while allowing for the increased turbulence due to the tidal action. At the seaward end of the estuary there is little deviation from the astronomical tidal rhythm, so the problem reduces to simple harmonic oscillations of salt water. Higher harmonics may be introduced as an extension of the simple solution. For a first approximation it is sufficient to consider flow in the longitudinal vertical plane, to assume that the pressure distribution is hydrostatic as in long wave theory, and even to neglect inertia terms when investigating net effects.
HURRICANE TIDE PREDICTION FOR NEW YORK BAY
Authors: Wilson Basil W.
Published: June 2017

This paper is concerned with the solution of the problem of correlating, on a two-dimensional basis, the meteorological parameters of several off-shore storms with the known surge induced by them in New York Bay and with the application of the results to the prediction of likely effects in New York Bay from a design hurricane of given strength traversing a given path at a given speed. A purely theoretical approach would have been beyond practical possibility within the time available for this study; the method adopted therefore is empirical but with some degree of theoretical guidance. A recursion formula is evolved, using the method of finite differences for time increments of 1/3 hour, which relates tide elevation at the bay-mouth with two values of the elevation at 1/3 and 2/3 hour earlier and with values of wind-stress and pressure-gradient driving-force components (directed towards New York Bay from several remote two-dimensionally spaced offshore-stations on the continental shelf) at times earlier by the periods taken for free long gravity waves to travel from the stations to the bay-mouth. The formula includes a comulative forcing function term which allows for the geostrophic influence of the earth's rotation and also for an "edge-wave" effect northward along the eastern seaboard. Moreover it takes into account the observed tendencies of hurricane storm tides in New York Bay to develop resurgences at periods of 7 hours with decay rates of 50% amplitude decrease per cycle. The coefficients of the "forcing functions", determined by correlation, tend to represent the storm size and speed and also the dynamic augmentation of the forced wave. Predicted maximum storm tide heights are in fair agreement with crude empirical estimates based on central pressures within the hurricanes. Predictions, however, provide complete time-sequences of water level for periods up to 24 hours inclusive of the first resurgence after the main surge.
EXPERIMENTAL DATA ON THE OVERTOPPING OF SEAWALLS BY WAVES
Authors: Paape A.
Published: June 2017

In the past it has been found that serious damage and breaching of seawalls is most frequently caused by overtopping. Hence for the design of seawalls data must be available about the overtopping by waves of the different profiles that might be possible. Naturally the conditions under which damage is caused to the seawall also depend on the type of construction and the materials used, for example: the stability of grass covered dikes can be endangered seriously by water flowing over the inner slope. In many designs the necessary height of a seawall has been defined such that not more than 2% of the waves overtop the crest, under chosen design conditions. This criterion has been determined on the assumption that the overtopping must remain very small. Some overtopping has to be accepted because no maximum value for wave height and wave run-up can be given, unless of course the wave height is limited by fore-shore conditions. Unfortunately this criterion gives no information about the volume and concentration of water overtopping the crest in each instance. Moreover it is of interest to know how this overtopping varies with other conditions, such as changes in the significant wave height. Information about the overtopping by waves was obtained from model investigations on simple plane slopes w^th inclinations varying from 1 : 8 to 1 : 2. The experiments were made in a windflume where wind generated waves as well as regular waves were employed. Using wind generated waves, conditions from nature regarding the distribution of wave heights could be reproduced. It appeared that the overtopping depends on the irregularity of the waves and that the same effects cannot be reproduced using regular paddle generated waves. In this paper a description of the model and the results of these tests are given. Investigations are m progress on composite slopes, including the reproduction of conditions for a seawall which suffered much overtopping but remained practically undamaged during the flood of 1953.
MODEL TESTS ON THE MOTION OF MOORED SHIPS PLACED ON LONG WAVES
Authors: Kilner F.A.
Published: June 2017

The equation of motion for a moored ship, subject to stationary wave action, is presented and discussed. The moorings are longitudinal, the ship is considered to be aligned to the direction of wave motion and positioned at a node, and the wave length is assumed long compared with the ship length. If the motion of the ship is assumed to be simple harmonic, and frictional forces between the ship and the water are neglected, an elementary analysis gives the required relation between the amplitudes of the ship's movement and of the water particle motion associated with the wave, A description is given of some tests carried out on model ships moored in a flume where stationary waves can be generated, and the amplitude and period can be varied independently. In these experiments, the amplitude of ship movement could be measured visually, or inferred from strain gauge readings, and the water motion was also observed. The results of these tests are compared with the simple theory. A table tilting harmonically is shown to be a mechanical analogy to stationary wave action on ships. The hydrodynamic mass for a ship moving in surge or sway motion is measured and is found to depend on the depth of water in which the ship is moored.
MODEL STUDY OF AN ISOLATED LIGHTHOUSE PLATFORM AT SEA (PRINCE SHOAL, QUEBEC)
Authors: Jarlan G.E.
Published: June 2017

Experiments on objects subject to wave forces have been made in the past, which led to formulae where the geometrical characteristics of the object are of primary importance. Other experiments, made on immersed objects, showed that the accelerative forces caused by wave impact are of the same order of magnitude as the drag forces associated with orbital velocities. In the case of a small free body completely immersed in a fluid and subject to a system of forces, other experiments showed that the fluid surrounding the body acquires a velocity while the flow field gains kinetic energy (Bef. 1). The acceleration of the object can be deduced from the pressure distribution around the body.
SAND TRANSFER, BEACH CONTROL, AND INLET IMPROVEMENTS, FIRE ISLAND INLET TO JONES BEACH, NEW YORK.
Authors: Saville Thorndike
Published: June 2017

Long Island, New York (Figure 1) extends for about 120 miles in a general east-west direction off the southern portions of the States of New York and Connecticut, from which it is separated by Long Island Sound. The western end of the island contains the Counties of Brooklyn and Queens which are part of New York City. To the east are the Counties of Nassau and Suffolk. The surface geology of Long Island is mostly of glacial origin. That portion of the south shore of Long Island with which this paper is concerned (Figure 2) consists of outwash plains of sand and gravel fringed by barrier beaches from 600 feet to 3,500 feet in width. They rise to about 15 feet above mean sea level, and in their natural condition are more or less protected by sand dunes which may reach an elevation of from 25 feet to 30 feet. The sand along the foreshore is predominantly quartz, averaging about 0.4 mm. at mid-tide level, and becoming somewhat finer offshore. The foreshore slope of the beaches averages about 1 on 10 above the mean low water line and about 1 on 30 immediately offshore. Several hundred feet offshore the slope flattens to about 1 on 250.