bluuebunny/crossref_metadata_2025 huggingface dataset:
PHASE-LOCKING OF MODES IN THE NEARSHORE: FIELD EVIDENCE
Authors: Haines J.W. , Bowen A.J.
Published: June 2019

Field investigations have shown that infragravity frequencies may dominate nearshore fluid motions (Bowen and Huntley, 1984). Theoretical studies have suggested that the modal structure of the infragravity field, including the degree of modal coupling, is important in generating complicated beach morphologies (Holman and Bowen, 1982) but previous analyses of field data have not provided a description of the infragravity field which is sufficiently detailed to assess the importance of these ideas. In this paper we present a statistical method which, when applied to data from any large sensor array, provides the desired description of the infragravity field. The method is applied to data from the NSTS (Nearshore Sediment Transport Study) experiment. The variance of the observed velocity field is described by a set of free wave modes. The results indicate that a complicated infragravity field composed of both edge waves and leaky modes is present. The modes modelled are also found to be significantly coupled over a range of modal pairs and frequencies.
DUNE STABILIZATION WITH A SAND/GEL COMPOSITE SYSTEM
Authors: Auerbach M.H. , Borden G.W. , Edge B.L.
Published: June 2019

The effectiveness of a novel sand/gel composite system for the temporary stabilization of coastal dunes was demonstrated in wavetank and field testing. The composite consists of 97% beach sand and water, with a few percent of a biodegradable aqueous polymeric gel made from nontoxic ingredients. The gel binds the sand into a firm but resilient composite that is natural in appearance and resists erosion from waves and tides. The composite is applied by pneumatic gun to the front face of a dune to a few feet below the berm level for toe protection. This paper describes the initial development and performance of the composite system in wavetank tests at the Oregon State University Wave Research Facility and field trials at Anastasia State Park, St. Augustine, Florida; Chuck's Steak House, Melbourne Beach, Florida; and Ocean Dunes Condominiums, Fort Fisher, North Carolina.
BEACH PROFILE CHARACTERISTICS DUE TO THE INCLINED WAVES
Authors: Hsu Tai-Wen , Ou Shan-Hwei
Published: June 2019

The result of a theoretical approach shows that the beach profile characteristics is governed by a modified Iribarren number which includes the effects among the factors of initial beach slope, wave angle and wave steepness. A series of experiments are conducted in a three-dimensional movable bed model on the conditions of two different initial beach slopes, two incident wave angles as well as several erosive wave steepnesses. The relative importance of each factor involved in the parameter is discussed. It is shown that the modified Iribarren number is effective in the analysis, of beach profile characteristics under the action of inclined waves. The empirical relationships between beach profile changes and the modified Iribarren number are proposed on the basis of experimental results.
SEDIMENT TRANSPORT ON NEARLY-PRISMATIC BEACHES
Authors: Stive Marcel J.F. , Roelvink J.A.
Published: June 2019

Recent progress in the quantitative modelling of the undertow has stimulated the modelling of cross-shore sediment transport. More so than before it seems now possible to attempt the dynamic modelling of beach profile development. Also, integration of dynamic cross-shore sediment transport formulations in horizontally two-dimensional models for watermotion and sediment transport has recently been suggested. This seems to be a first step of integrating depth-averaged 2DH-modelling with 2DV-profile- modelling. Here an overview is given of these developments and the understanding gained sofar of the several current systems and the induced sediment transport and morphology that are found in the situation of random waves normally and obliquely incident on beaches which vary not or only slowly alongshore.
WAVE GROUPS ON WAVE RECORDS MEASURED ALONG SPANISH SHORES
Authors: Maron Adolfo
Published: June 2019

A large amount of wave records measured at four different locations of the Spanish shores have been analysed from the point of view of wave group formation. The influence of wave climate and depth on the results is studied. The results are compared with existing theories for runs of waves, SIWEH and envelope functions. Characteristics of extreme groups are also considered.
THE CRITERION OF RIPPLE FORMATION BY WAVE ACTION
Authors: Tsuchiya Yoshito , Banno Masato
Published: June 2019

In this paper, we emphasize that there must exist a common mechanism governing ripple formation in the case of both waves where the acceleration effect exists, and unidirectional flow, where the acceleration effect is usually ignored. Using a light sediment with an immersed specific gravity of about 0.8, which is nearly one-half that of natural sand, a series of ripple formation experiments were performed in order to determine the formation criterion. Using the experimental data, along with data collected by other researchers the ripple-formation criterion was investigated in terms of the ratio of water particle orbital diameter to sediment grain diameter as an acceleration parameter, on the so-called Shields diagram. Emphasis is placed on the importance of this ratio in the criterion of ripple formation in relation to that by unidirectional flow.
EXTREME EROSION EVENT ON AN ARTIFICIAL BEACH
Authors: Moller J.P. , Swart D.H.
Published: June 2019

At Oranjemund just north of the mouth of the Orange on the South-West African/ Namibian coastline the Consolidated Diamond Mines (Pty) Limited (CDM) is mining for diamonds in the inshore area. They use an artificially-built seawall of sand to keep the sea out of the paddocks which are being stripped and mined at bedrock level, which is well below sea level. The seawall runs parallel to the original shoreline at a distance of up to 350 m offshore. The beach profile is correspondingly very steep and under most conditions offshore sediment losses occur, which are compensated for by artificial nourishment. During February 1987 offshore losses of about 120 m per running metre of seawall were recorded from above the waterline. In this paper a data set is presented to serve as a basis for the calibration of on-offshore sediment models and some simulations are reported on.
ARE SOLITARY WAVES THE LIMITING WAVES IN LONG WAVE RUNUP?
Authors: Synolakis Costas Emmanuel
Published: June 2019

This is a study of the maximum runup of single long waves on plane beaches. Laboratory data are presented that suggest that solitary waves attain the higher runup distances than other single long waves with identical generation characteristics, such as energy or momentum. These results suggest that solitary waves may provide a limiting condition for long wave runup on plane beaches.
CHARACTERISTICS OF SHINGLE BEACHES WITH REFERENCE TO CHRISTCHURCH BAY, S. ENGLAND
Authors: Nicholls Robert , Webber Norman
Published: June 2019

The rapid recession of the shingle bank of Hurst Beach (up to 3.5m/yr) makes it an excellent natural laboratory for the study of the factors which influence the stability of shingle beaches. Studies have included: the significance of long period, high energy, swell waves - the classification and quantification of overwash processes - run-up and seepage characteristics - the effect of settlement of the underlying strata - and the implications for practices in shingle nourishment. The studies have revealed the distinctive character of shingle beaches as compared with the more fully researched sand beaches. More detailed research on shingle beaches is justified particularly in relation to (i) the run-up characteristics including its interaction with swash cusps and (ii) the influence of the subsidiary sand fraction on the beach characteristics.
ON BERM BREAKWATERS
Authors: Torum Alf , Naess Steiner , Instanes Arne , Vold Svein
Published: June 2019

Two and three dimensional laboratory studies have been carried out on the stability of a berm breakwater concept. The study has to some extent been general and to some extent been connected to a project study of the stability of a berm breakwater for the fishing port of Arviksand, Norway.
RELIABILITY ANALYSIS OF RUBBLE-MOUND BREAKWATERS
Authors: Mizumura Kazumasa , Yamamoto Masato , Endo Taiji , Shiraishi Naofumi
Published: June 2019

To verify the effect of wave period on the motion of concrete blocks in rubble-mound breakwaters, simple physical models are employed and their motion is investigated by the numerical simulation. Finally, risk or reliability are calculated and the weight of concrete blocks for given physical condition is discussed by them.
RELIABILITY BASED DESIGN OF RUBBLE-MOUND BREAKWATER
Authors: Yamamoto Masato , Mizumura Kazumasa , Endo Taiji , Shiraishi Naofumi
Published: June 2019

The object of this present research is to study probabilistic design of armor blocks protecting composite breakwaters and to produce optimum design methodology for S-shaped breakwaters in terms of failure probability and construction cost. Failure probability in the vicinity of the still water level is greatest in the case of uniform sloped breakwaters. Therefore,S-shaped breakwaters of which the slope near the still water level is milder have a reduced risk of damage compared to uniform sloped ones. The optimum design index presents good economics and reliability in rubble-mound breakwater design.
SEAWALLS AND SHORELINE PROTECTION
Authors: Van de Graaff Jan , Bijker Eco W.
Published: June 2019

All over the world shore-parallel constructions (seawalls; revetments; bulkheads) suffer from damage. It is argued that these constructions are in fact frequently built at places where they shouldn't.
QUALITY AND DURABILITY OF CONCRETE ARMOUR UNITS
Authors: Van Damme L. , Taerwe L. , Dedeyne R. , De Rouck J.
Published: June 2019

The reliability of rubble mound breakwaters not only depends on the hydraulic stability but to a large extent on the strength of the armour units as well. In the debate on the shape of armour units, which turns out quite often to be merely academic in nature, generally too little attention is paid to the question of structural strength. On the occasion of the realization of the new outer harbour at Zeebrugge (Belgium) a serious effort has been made to arrive at a better understanding in the behaviour of concrete as construction material for armour units. This contribution gives an overview of the routine tests and of some particular investigations, carried out with respect to quality and durability of concrete armour units.
WAVE FORCE ON BREAKWATERS WITH CONCRETE BLOCK MOUN
Authors: Hattori Masataro , Inagaki Keiji , Noguchi Yuuji , Endo Taiji
Published: June 2019

Analytical theory is derived for prediction of the wave force acting on a upright structure armored by concrete block mound of rectangular shape. The theoretical treatment starts from the linear long wave theory and the flow resistance in the mound is described by a linearized friction law. As a practical application of the theory, approximate method for the structure with sloping block mound is proposed. Experiments are conducted to verify the theory and approximate method.
BLOCK REVETMENT DESIGN WITH PHYS. AND NUM. MODELS
Authors: Bezuijen A. , Wouters J. , Laustrup C.
Published: June 2019

A combination of a physical model and numerical models has been used in the design of a block revetment for the Danish North Sea coast. The wave pressure loading on the revetment during design conditions was investigated in a physical scale model. The measured wave pressures were used as a boundary condition for the numerical models. Solutions for the flow equations through the coverlayer, filter layer and subsoil were then obtained in the numerical models, taking into account the influence of turbulence. With these solutions the stability of the coverlayer and subsoil was evaluated. The paper presents a description of the various models and information about the design of the revetment.
WATER WAVE SCATTERING BY ROWS OF CIRCULAR CYLINDERS
Authors: Dalrymple Robert A. , Seo Seung Nam , Martin Paul A.
Published: June 2019

The scattering of waves by a finite number of rows of circular cylinders is examined. Reflection and transmission coefficients are obtained and compared to Kakuno's experimental data. Following Twersky (1962), the scattering from a single row of cylinders (or the single grating problem) is numerically solved. The wide-spacing approximation is used to find the effect of multiple gratings.
A NEW TYPE OF BREAKWATER UTILIZING AIR COMPRESSIBILITY
Authors: Ikeno Masaaki , Shimoda Naokatsu , Iwata Koichiro
Published: June 2019

This paper is to investigate both theoretically and experimentally the wave energy dissipation and air-pressure variation of a new type of breakwater having a pressurized air-chamber and two buoyancy tanks. The theoretical models are developed in this paper and they are shown to be in good agreement with experimental values. The new type of breakwater proposed in this paper is pointed out to attenuate the transmitted wave much better than the rectangular-shaped and concave-shaped breakwaters without the air-chamber.
ARMOUR UNIT STRUCTURAL RESPONSE - A PARAMETRIC STUDY
Authors: Anglin C. David , Baird William F. , Mansard Etienne P.D. , Scott R. Douglas , Turcke David J.
Published: June 2019

There is a general lack of knowledge regarding the nature and magnitude of loads acting on armour units used for the protection of rubblemound coastal structures. Thus, a comprehensive design procedure incorporating both the hydraulic stability and the structural integrity of the armour units does not exist. This paper presents the results of a detailed parametric study of the structural response of armour units to wave-induced loading in a physical breakwater model. The effect of the following design parameters is investigated: breakwater slope, armour unit location, wave period and wave height. This research has made a number of significant contributions towards the development of a comprehensive design procedure for concrete armour units. It has identified a linear relationship between the wave-induced stress in the armour units and the incident wave height. In addition, it has shown that the conditional probability of waveinduced stress given wave height can be estimated by a log-normal distribution. Finally, a preliminary design chart has been developed which incorporates both the structural integrity and the hydraulic stability of the armour units.
DESIGN AND CONSTRUCTION OF BERM TYPE BREAKWATERS
Authors: Baird William F. , Davidson D.D. , Edge Billy , Magoon Orville T. , Rauw Charles I. , Treadwell Donald
Published: June 2019

The standard design for a rubble-mound breakwater as reported in recent text books and manuals has consisted of a core of rubble quarry-run that is protected from wave action by two layers of relatively large quarried stone or concrete units. Filter layers of intermediate size stone are recommended beneath the armour layer to prevent loss of the core material through the armour. The pioneering work of Hudson provides coefficients for a formula that allowed widespread use of this design concept throughout the world. A breakwater of this form tends to require the smallest volume of stone; however, it may not represent the least cost structure for a specific location because of the cost and availability of local materials. Recently, design engineers and hydraulic laboratories have given considerable attention to alternative forms of rubble mound structures. The objective of this work has been to minimize cost while maintaining the same or improved level of stability when the breakwater is subjected to extreme wave conditions. Principally, emphasis has been given to the utilization of locally available quarried stone and to maximizing the use of the full yield of a local quarry. This has required the design of breakwaters using smaller armour stone and a wider range of sizes than was used in the more conventional breakwater. These designs have also given consideration to the realities of construction and the limitation of construction equipment on the assumption that cost savings will be achieved with relatively simple construction methods. Clearly the use of smaller armour stones requires a change in other properties or characteristics of the armour layer, compared to a conventional design, in order to achieve the same stability. The principal characteristics of a berm breakwater are the high permeability of the armour-layer and the significantly larger volume of armour. Berm breakwaters generally consist of a relatively large and permeable mass of armour stone (of smaller size than required for a conventional design).
WAVE FORCE ON A CURTAIN-WALL-TYPE BREAKWATER DUE TO OBLIQUELY INCIDENT WAVES
Authors: Sekimoto Tsunehiro , Kondo Kosuke , Ohshimo Tetsunori
Published: June 2019

Assessment of the characteristics of the wave force on the curtain-wall-type breakwater, due to obliquely incident waves, was conducted through numerical calculation, laboratory and field experiments. In the numerical calculations, the Boundary Integral Equation Method (BIEM) for obliquely incident waves was used. From the results of calculation and laboratory experiment, design graphs for estimating design wave force were established and the validity of the diagrams was verified through comparison with the results of laboratory and field experiments.
ENTRAINMENT DUE TO MEAN FLOW IN TWO-LAYERED FLUID
Authors: Ura Masaru , Matsunaga Nobuhiro
Published: June 2019

The entrainment phenomena have been investigated across an interface between two-layered stratified flow induced by wind shear stress. The velocities of mean flow, turbulence and entrainment have been measured under three different conditions of water surface by using a wind-wave tank. When the entrainment velocity ue is expressed on the basis of the turbulent quantities at the interface, the turbulent entrainment coefficient E ( = ue/u) is given by E = A-(egl/u2)-3I1 ( A = 0.7). Here Eg, u and 1 are the effective buoyancy, the turbulence intensity and the integral lengthscale of turbulence at the interface, respectively. This result coincides with the relationship of entrainment due to oscillating grid turbulence, in which the mean flow does not exist. When, for the practical purpose, the estimation of ue is made by using the mean velocity Um and the depth h of mixed layer, Em ( - Ue/Um ) = Am-(egh/Um 2)"3/2 is derived from the transformation of E = A-(egl/u2)-3/2. There holds Am = A-Tf between Am and Tf, Tf being a turbulence factor given by (u/Um)4-(1/h)-3/2. It has been found that this relationship is also valid in various types of two-layered stratified flows as well as the wind-induced two-layered flows.
BOUNDARY CONDITIONS IN FINITE ELEMENT MODELING OF STRATIFIED COASTAL CIRCULATION
Authors: Christodoulou George C. , Economou George D.
Published: June 2019

The effect of boundary conditions on numerical computations of stratified flow in coastal waters is examined. Clamped, free radiation and sponge layer conditions are implemented in a two-layer finite element model and the results of simple tests in a two-layer stratified basin are presented.
NEARSHORE CIRCULATIONS ON A WAVY COAST
Authors: Lin Ming-Chung , Hwang Sheng-Yeh
Published: June 2019

Nearshore circulations, produced by wave-induced radiation stress gradients, form different circulation patterns under different wave characteristics and topographical conditions. Although numerous studies of nearshore circulations, such as Bowen (1969), Miller and Barcilon (1978), Dalrymple & Lozano (1978) and so on, have been appeared in the literature, it seems that little attention is paid on the case of a non-straight shoreline. O'Rorske & Leblond (1972) have investigated the wave-induced longshore currents in a semicircular bay, while Oda (1982) has used the coordinate transformation to treat nearshore circulations on a circular-arc shaped coast. Lin and Lee (1982), introduced a small perturbation quantity of wave set-up and set-down, induced by the non-straight shoreline, into the mean total water depth to obtain a governing partial differential equation by which they investigated the nearshore circulations on a cuspate coast. In Lin and Liou (1986), a more general equation was deduced on the orthogonal curvlinear coordinate system to unify the diversities among the related theories, and moreover, to investigate the nearshore circulations on the arc-shaped coast.
STEEP SLOPE SEAWATER SUPPLY PIPELINE
Authors: Lewis Lloyd F. , Van Ryzin Joseph , Vega Luis
Published: June 2019

The State of Hawaii's Ocean Science and Technology (HOST) Park, the U.S. Department of Energy (DOE), and the Pacific International Center for High Technology Research (PICHTR) sponsored the construction and installation of an expanded seawater supply system at the Natural Energy Laboratory of Hawaii (NELH). This effort included the installation of a 1.0m diameter high density polyethylene pipe capable of delivering 840 1/s of cold seawater, representing the longest (2,060m) large diameter pipe traversing the steepest slope ever spanned. Acceptance testing of the system was completed in June 1988 and the design service life is 10 years.
COASTAL AND ESTUARINE HYDRODYNAMIC MODELING IN CURVILINEAR GRIDS
Authors: Sheng Y. Peter , Wu T.S. , Wang P.F.
Published: June 2019

A time-dependent three-dimensional numerical model of coastal and estuarine circulation, which allows the use of generalized curvilinear grids to resolve the complex shoreline geometry and bathymetry, has been developed. Model formulation is briefly presented, followed by example model applications to such water bodies as Lake Okeechobee, James River and Chesapeake Bay.
A COMPARISON BETWEEN GERMAN AND NORTH AMERICAN TIDAL INLETS
Authors: Dieckmann Reinhard , Osterthun Manuela , Partenscky Hans Werner
Published: June 2019

Initial results are presented relating to an investigation of geomorphological parameters from 26 of a total of 28 tidal inlets and 11 coastal structures similar to inlets along the German Bight. The following parameters were investigated: - tidal prism - inlet area relationship, - cross-sectional form and depth, - location of the channel within the cross-section, - ebb tidal deltas and - the structures of the back barrier regions. The most important parameter governing the shaping process of these coastal structures is considered to be the tidal volume. The results of the investigations were compared with data from American publications. Despite the differences between the regions studied, in overall terms, surprizingly good agreement was obtained between the parameters investigated. Notable differences exist only in relation to the morphological structure of the back barrier regions (tidal flats, salt marshes, open water lagoons). In respect of the latter differences, a short account is given of the biological and climatological influencing factors.
WAVE-CURRENT INTERACTION IN HARBOURS
Authors: Kostense Jan K. , Dingmans Maarten W. , Van den Bosch Peter
Published: June 2019

A finite element model has been developed to study the effect of currents on the wave propagation in and around arbitrarily shaped harbours of variable depth. The model solves an elliptic mild-slope type of equation for time-harmonic waves, and thus circumvents the limitations of existing models for wave-current interaction in coastal areas, which apply a parabolic approximation. Numerical examples are presented, both for schematized cases, as the effect of "rip currents" on normal incident waves on a sloping beach, and for a realistic geometry.
FLOW DEPENDENCY OF BOTTOMSTRESSES IN TIDAL MODELS
Authors: Leendertse Jan J. , Langerak A.
Published: June 2019

In modeling studies the bottomstress parameter may not be taken as a constant for making predictions. This is particularly true when large changes are being made in the water bodies. Engineering judgement is than necessary as studies to a relation between the bottomstress parameter and tidal flow velocity are not conclusive.
NUMERICAL MODELLING OF SUSPENDED SEDIMENT TRANSPORT IN THE LOIRE ESTUARY
Authors: Teisson Ch. , Fritsch D.
Published: June 2019

In order to evaluate silt displacements and deposits in the outer part of the Loire Estuary over one year, a two-dimensional depth-integrated model of suspended sediment transport has been carried out. It takes into account transport and dispersion of suspended sediment by tidal currents, and processes of erosion, deposition and bed consolidation. Erosion laws and consolidation laws are specific of the Loire Estuary and come from laboratory experiments. Representative tidal conditions and river Loire flowrates have been identified : results of the model for these typical cases will be tentatively extrapolated to a one year evolution.
SUBMARINE SIPHONS FOR ATHENS SEWERAGE SYSTEM
Authors: Eisenberg Y. , Gofas Th. C. , Fasano R.A. , Hindes F.S.
Published: June 2019

The submarine siphons with an overall length of almost 1300 meters and an ultimate capacity of 27 cubic meters (m^) per second (about 600 million gallons per day) will be a major element of the new wastewater conveyance and treatment system presently under construction in Athen, Greece. This will help alleviate the present condition where an average of more than 6 m^ per second (130 million gallons per day) of untreated domestic and industrial wastewater are discharged into the sea near Athens. Construction of the submarine siphon pipes started in late 1984 and was completed in early 1987. Description of the data collection for and the design, manufacture and construction of these submarine siphons are presented in this paper.
QUANTIFICATION OF LONGSHORE SAND TRANSPORT
Authors: Yeend John S. , Hatheway Darryl J.
Published: June 2019

The intent of this paper is to express the quantities

of sand bypassed by a sand transfer facility and

transported in the littoral drift at the South Lake Worth

Inlet, Palm Beach County, Florida. Discussion on littoral

transport volumes will include estimates of the annual

average drift from 1948 to 1987, and discussions of sand

bypassing quantities will include improvements in the

estimation of pumping rates.
UTILIZATION OF MOORED VESSELS IN HYDRAULIC MODELS OF HARBORS
Authors: Guarga Rafael , Goldsztejn Eduardo , Puntigliano Fernando
Published: June 2019

The behavior of the model of a moored vessel in a harbor's hydraulic model (Froude's model) is studied, taking into account the difficulties arising from the fact that modelling a moored vessel requires to incorporate the Reynolds number. Experiments made with the model of a large grain carrier at a 1/175 scale are shown. The horizontal motions of this ship due to the waves were measured when it is moored in a zone in which the length scale along the vertical axis was modified (vertical distortion), and the influence of different depths on these motions was studied. This study was performed in order to be able to use this ship model for the evaluation of different alternatives of harbor design, in the building of new facilities at a port placed in the Atlantic coast of Uruguay.
SOME CHARACTERISTICS OF BREAKING WAVES
Authors: Raichlen Frederic , Papanicolaou Panos
Published: June 2019

In recent years there has been a surge in coastal engineering research devoted to various aspects of breaking waves including their kinematics at and after breaking. For a review of certain aspects of this field the interested reader is referred to Peregrine (1983) and Battjes (1988); in this discussion only certain publications pertinent to this investigation will be mentioned briefly. With the advent of laser-Doppler velocimetry (LDV) a number of investigators have measured the internal velocities of waves both before, at, and after breaking. For example, Nadaoka (1986) measured the velocities in the shoaling region under periodic breaking shallow water waves. This extensive study of the nearshore regions resulted in vector diagrams which described very well several spatial aspects of the flow shoreward of breaking. Skjelbreia (1987) also used LDV techniques to define the kinematic characteristics of breaking solitary waves. Measurements were made of the water particle velocities under spilling and plunging breaking waves both very near breaking and after breaking, close to the water surface and to the bottom. A high degree of reproducibility was possible with the laboratory wave generation system used so experiments were conducted at different locations with essentially the same wave; this will be discussed more fully later. Skjelbreia (1987) also presented vector diagrams of the velocities under plunging and spilling solitary breakers. These measurements when compared to those of Nadoaka (1986) raise several questions regarding similarities and differences between breaking oscillatory waves and waves of translation. In addition to detailed kinematic measurements, a macroscopic view of shoaling solitary waves was also taken by Skjelbreia (1987) yielding results on the variation of the wave height with distance both before and after breaking. Although there has been a considerable amount of work along these lines in the past, observations of the changes in the wave at and after breaking are still quite useful in developing an overall understanding of the breaking process.
OBSERVATION OF DIRECTIONAL WAVE SPECTRA AND REFLECTION COEFFICIENT OF BREAKWATER IN A HARBOR
Authors: Ohshimo Tetsunori , Kondo Kosuke , Sekimoto Tsunehiro
Published: June 2019

Field investigations were performed in order to show the effect of wave diffraction by breakwaters through directional wave spectra measurements in a harbor, and to estimate the reflection coefficient by resolving the incident and reflected wave energy in front of a composite type breakwater. Combinations of an ultrasonic wave gage (USW) and an electromagnetic current meter (EMC) were used to measure the synchronized data of the water surface elevation and two horizontal velocities. The EMLM (Extended Maximum Likelihood Method) was applied for the calculation of the directional wave spectrum, and the modified EMLM for an incident and reflection wave field was applied for the estimation of the reflection coefficient. Through the estimated directional wave spectra, the effect of wave diffraction by breakwaters were discussed and the reflection coefficient was estimated at about 0.9. As a result, the applicability of the field investigation method and the modified EMLM were verified.
VERIFICATION OF NUMERICAL WAVE PROPAGATION MODELS IN TIDAL INLETS
Authors: Vogel J.A. , Radder A.C. , De Reus J.H.
Published: June 2019

The performance of two numerical wave propagation models has been investigated by comparison with field data. The first model is a refractiondiffraction model based on the parabolic equation method. The second is a refraction model based on the wave action equation, using a regular grid. Two field situations, viz. a tidal inlet and a river estuary along the Dutch coast, were used to determine the influence of the local wind on waves behind an island and a breaker zone. It may be concluded from the results of the computations and measurements that a much better agreement is obtained when wave growth due to wind is properly accounted for in the numerical models. In complicated coastal areas the models perform well for both engineering and research purposes.
SPECTRAL WAVE ATTENUATION BY BOTTOM FRICTION: THEORY
Authors: Madsen Ole Secher , Poon Ying-Keung , Graber Hans C.
Published: June 2019

Based on the linearized form of the boundary layer equations and a simple eddy viscosity formulation of shear stress, the turbulent bottom boundary layer flow is obtained for a wave motion specified by its directional spectrum. Closure is obtained by requiring the solution to reduce, in the limit, to that of a simple harmonic wave. The resulting dissipation is obtained in spectral form with a single friction factor determined from knowledge of the bottom roughness and an equivalent monochromatic wave having the same root-mean-square near-bottom orbital velocity and excursion amplitude as the specified wave spectrum. The total spectral dissipation rate is obtained by integration and compared with the average dissipation obtained from a model considering the statistics of individual waves defined by their maximum orbital velocity and zero-crossing period. The agreement between the two different evaluations of total spectral dissipation supports the validity of the spectral dissipation model.
PROPAGATION OF WIND WAVES ON TIDES
Authors: Tolman Hendrick L.
Published: June 2019

Effects of instationary depths and currents in tides on shelf seas on wind wave propagation are investigated using two numerical models in two academical situations representing shelf sea conditions. It is shown that changes in absolute frequency, which are induced by the instationarity of depth and current, are significant in contrast to what is usually assumed. If these changes are neglected large and unpredictable errors may occur in calculated changes of wavenumber and amplitude.
DIRECTIONAL SPECTRUM ESTIMATION FROM A BAYESIAN APPROACH
Authors: Hashimoto Noriaki , Konbune Koji
Published: June 2019

A new directional spectral estimation method using a Bayesian approach is proposed. The proposed method is examined for numerical simulation data, and the validity of the method is discussed. Some examples of the directional spectra estimated from field observation data attained at an offshore oil rig utilizing seven wave probes are also shown in this report. The major conclusions of the report are : (1) The proposed method can be applied for more than four arbitrarily mixed instrument array measurements. (2) It has a higher resolution power than other existing methods for estimating directional spectrum. (3) It is a better method for estimating directional spectra from the cross-power spectra contaminated with estimation errors. (4.) It is more adaptable to reformulation of the estimation equations as the study of structures of directional spectrum progesses.
THE WAMS MODEL APPLIED TO THE MEDITERRANEAN SEA
Authors: Cavaleri Luigi , Bertotti Luciana , De Luis Jose E. , Lionello Piero
Published: June 2019

The application of an advanced third generation wave model to the Mediterranean Sea is described. The model is based on the physical description of the wind wave evolution, avoiding any shortcoming in the estimate of the single terms that contribute to the energy budget. The capability of the model to respond to any meteorological situation is illustrated by applying it to a severe storm occurred in January 1987. The results show that the crucial point for the final accuracy lies in the correct evaluation of the wind field.
ON THE OCCURRENCE OF ABNORMAL STORMS AND ITS IMPLICATIONS ON DESIGN PARAMETERS (STATISTICAL ANALYSIS OF STORMS)
Authors: Jensen Ole Juul , Klinting P.
Published: June 2019

The assessment of design parameters has a fundamental importance for port planning and design of coastal structures. Special emphasis has to be put on the importance of the occurrence of abnormal storms. The authors' experience from investigations of port projects has revealed that on many sites it is storms with unusual tracks or otherwise unusual behaviour that are determinant for the design events. This experience is documented by two case stories. The importance of unusual weather systems is discussed and statistical methods for investigation of such phenomena are discussed.
WAVE OVERTOPPING ON RUBBLE MOUND BREAKWATERS
Authors: Aminti Pierliugi , Franco Leopoldo
Published: June 2019

The paper gives the results of an extensive series of hydraulic model tests carried out in a random wave flume, in order to study the effects on wave overtopping of the main geometric parameters of a typical rubble mound breakwater with crown wall. The results have been compared with those from other studies and analyzed with different methods. Generalized design diagrams and formulae for the prediction of overtopping discharges are finally given for a large number of popular breakwater configurations.
REFLECTIONS FROM COASTAL STRUCTURES
Authors: Allsop N.W.H. , Hettiarachchi S.S.L.
Published: June 2019

Wave reflections at and within a coastal harbour may make a significant contribution to wave disturbance in the harbour. Reflected waves may lead to danger to vessels navigating close to structures, and may reduce the availability of berths within the harbour. Wave reflections may also increase local scour or general reduction in sea bed levels. In the design of breakwaters, sea walls, and coastal revetments, it is therefore important to estimate and compare the reflection performance of alternative structure types. In the use of numerical models of wave motion within harbours, it is essential to define realistically the reflection properties of each boundary. This paper presents results from a study of the reflection performance of a wide range of structures used in coastal and harbour engineering.
REALIZABLE WAVE PARAMETERS IN A LABORATORY FLUME
Authors: Funke E.R. , Mansard E.P.D. , Dai G.
Published: June 2019

In order to establish a sound basis for the methodology deployed for the generation of realistic waves under laboratory conditions, a comparison is presented between numerical and physical realizations derived from the Random Phase and the Random Complex Spectrum method for wave synthesis. The comparisons are made in terms of 12 critical wave parameters, including three wave grouping parameters. The results indicate that, for the physical realizations of the limited conditions tested, the two methods give compatible results which fall within the expected band of variability. All physical waves undergo some evolutionary change during propagation which affects predominantly the spectral characteristics. For physical waves produced by the Random Phase method, this change increases the variability of some wave parameters. A sample analysis of one case, applying second order wave and wave generation theory to a numerical simulation, suggests that certain differences between numerical and physical simulations can be explained by non-linear wave theory.
ON THE METHODOLOGY OF SELECTING DESIGN WAVE HEIGHT
Authors: Goda Yoshimi
Published: June 2019

A statistically-rational method of extreme wave data analysis is presented. A combination of the Fisher-Tippett type I and the four Weibull distributions is proposed as the candidates of distribution functions. The least square method is used for data fitting. The best plotting position formula for each function is determined by the Monte Carlo method with 10,000 simulations per sample size. Confidence intervals of estimated extreme wave heights for given return periods are evaluated by simulations and expressed in the form of empirical formulas, for both the cases when the true distribution is known and unknown. An example of extreme wave data analysis is given.
ON THE TRANSFORMATION OF WAVE STATISTICS DUE TO SHOALING
Authors: Mansard E.P.D. , Funke E.R. , Readshaw J.S. , Girard R.K.
Published: June 2019

The results of a 1:40 scale physical model investigation into the shoaling process are described. The model simulated a nearly constant slope of 1:40 with wave measurements made at a depth of approximately 25 and 9 m. Two hundred individual tests were undertaken, with four offshore significant wave heights as the only test variant. The results indicate that the most severe nearshore wave conditions do not occur with the worst offshore conditions. There is evidence of a significant increase in low frequency wave energy in the nearshore zone.
DYNAMIC WAVE SETUP
Authors: Lo Jen-Men
Published: June 2019

The wave setup for a given wave spectrum was re-evaluated with the radiation stress term including the low-frequency terms. This setup which is referred to here as "dynamic wave setup", was compared with the steady setup, which is generated by including only the non-periodic radiation stress terms. The results of the study showed that the dynamic wave setup is greater than the steady wave setup, sometimes almost double its value. Therefore, the dynamic wave setup is important for engineering applications, particularly in the study of storm surges and coastal engineering problems.
PORE PRESSURE INDUCED BY WIND WAVES IN SAND BED
Authors: Massel S.R. , Kaczmarek L.
Published: June 2019

The two projects (LUBIATOWO 79 and LUBIATOWO 86) were aimed at study pore pressure behaviour in natural sand bed in the coastal zone of the Baltic sea under the action of storm waves. During both projects, the wave induced pore pressures at the various levels in the sea bed were measured. The collected data were used to verify the applicability of the various theoretical approaches. In the conclusion, the range of the application of the particular analytical method is given.
A NUMERICAL MODEL OF NEARSHORE CURRENTS DUE TO IRREGULAR WAVES
Authors: Yamaguchi Masataka
Published: June 2019

This paper presents a numerical model of nearshore currents due to irregular waves. The radiation stress is estimated by a current-depth refraction model for irregular waves, in which the energy dissipation due to wave breaking is modeled through the use of a saturated frequency spectrum in shallow water. The model is in reasonable agreement with measured wave height, mean water level variation and observed nearshore current patterns. Next, the model is applied to the computation of wave transformation and nearshore currents on a uniformly sloping beach and on model topographies with complicated contour lines. Comparison with the results based on a regular wave model shows that wave irregularity has a smoothing effect on cross-shore distributions of wave height, mean water level variation and longshore currents, but that it does not have much effect on nearshore current patterns.
STUDY OF SHELF WAVES VS SAND DRIFT IN NW COAST OF TAIWAN
Authors: Hou Ho-Shong
Published: June 2019

For the planning and design of harbor and coastal Engineering, most important affected factors are waves and Littoral drift. This research deals with analysis of the measured waves and the budget of the beach material whether it is deposited or scoured in the North-western coast of Taiwan; and the relationship between wave energy and littoral transport rate. For processing this research the field Survey wave measurement, sand sampling, and echo sounding is necessitated. The objective of this research is to establish the model of waves and littoral transport budget. Therefore, the results of this research are planned to submit to the planning and design of harbor and coastal engineering works of the Taiwan west sandy coast. The main contains of this research are consisted of (1) Analysis, observations and investigations of the field oceanographic data, winds, waves, coastal geomorphology and littoral drift of the North-western coast of Taiwan. (2) Analysis of the shelf waves from the actual measured wave records. (3) Research of the wave decaying process of the continental shelf waves. (4) Statistical research of the measured waves and establishment of the practical model of the relationship between the shelf wave energy and the littoral transport rate in the north-west coast of Taiwan.
TOWARD AN IMPROVED EMPIRICAL FORMULA FOR LONGSHORE SAND TRANSPORT
Authors: Kraus Nicholas C. , Gingerich Kathryn J. , Rosati Julie Dean
Published: June 2019

This paper presents results of two field experiments performed using portable traps to obtain point measurements of the longshore sand transport rate in the surf zone. The magnitude of the transport rate per unit width of surf zone is found to depend on the product of the local wave height and mean longshore current speed, but correlation is much improved by including two correction terms, one accounting for local wave energy dissipation and the other for the fluctuation in the longshore current. The field transport rates are also found to be compatible with laboratory rates obtained under combined unidirectional and oscillatory flow. Total transport rates previously reported for this experiment program are revised with recently determined sand trapping efficiencies.
INCOMING AND OUTGOING WAVE INTERACTIONS ON BEACHES
Authors: Tatavarti V.S.N. , Huntley David A. , Bowen Anthony J.
Published: June 2019

A technique to decompose colocated random field measurements of wave elevation and current velocity into incoming (shoreward propagating) and outgoing (seaward propagating) components is presented. This decomposition technique, which is less sensitive to noise, enables us to determine the frequency dependent reflection coefficients and also the relative phase between the incoming and outgoing waves. The method is applied to C2S2 and NSTS data sets, from beaches with wide ranging characteristics and wave regimes. The results demonstrate the selective nature of beach absorption/reflection characteristics but are inconclusive in terms of a proper parameterization of reflections on natural beaches
CALCULATION OF ON-OFFSHORE SAND MOVEMENT AND WAVE DEFORMATION ON TWO-DIMENSIONAL WAVE-CURRENT COEXISTENT SYSTEM
Authors: Kinose Koichi , Okushima Shuji , Tsuru Masahito
Published: June 2019

In this paper, we proposed a method of calculation to predict quantitatively the on-offshore sand movement and the wave deformation on a wave-current coexistent system by assuming a river mouth. And the calculated results were compared with the experimental data obtained for the coexistent system in a twodimensional wave tank. The distribution of wave height on the breaker zone was analyzed by use of BORE MODEL. It was required for the calculation of the sand transport rate. The model was established on the assumption that the value of energy loss in a breaking wave was equivalent to that of bore. The wave height distribution on the offshore side of breaking point was presumed employing the third order approximate solution of Stokian wave on the coexistent system. The breaking point was obtained by use of Miche's criteria equation. The local sand transport rate could be calculated by use of POWER MODEL. The predominant direction of sand drift was recognized using relations for judgement which were derived from the experimental results. The transformation of sea bottom and river one was estimated on the basis of the calculated distributions of the wave height and the sand transport rate. The results obtained by this analytical method agreed well with the experimental results.
COASTAL PROCESSES IN GUARDAMAR BAY (SPAIN)
Authors: Chapapria Vicent J. de Esteban , Gonzalez J. Javier Diez , Parra Miguel Arenillas , Gimeno Rafael Cortes
Published: June 2019

The surrounding coastal area of the Segura's River mouth has registered in the last years many erosion problems. It is one of the biggest coastal conjunct in the Spanish mediterranean coast. A whole of studies was carried out to determine littoral and coastal processes in this area.
Complete Proceedings - Single PDF Download
Authors: Edge Billy L.
Published: June 2019

This book contains over 220 papers presented at the 21st International Conference on Coastal Engineering. The book is divided into six parts: theoretical and observed wave characteristics; coastal processes and sediment transport; coastal structures and related problems; coastal, estuarine and environmental problems; case studies; and ship motions. The individual papers include such topics as the effects of wind, waves, storms and currents, erosion, sedimentation, and beach nourishment. Special emphasis is given to case studies of completed engineering projects. With the inclusion of both the theoretical and the practical, these papers provide the civil engineer with a broad range of information on coastal engineering.