bluuebunny/crossref_metadata_2025 huggingface dataset:
DISCONTINUOUS COMPOSITE WAVE ABSORBER STUDIES
Authors: Fallon Anthony R.
Published: June 2019

An experimental study was conducted to determine the energy dissipation characteristics of a discontinuous wave absorber consisting of an impervious lower slope and a stone-filled upper slope. The purpose was to determine the wave energy absorption as a function of the incident wave parameters and the wave absorber geometry. Parameters varied were wavelength, wave height, lower and upper absorber slopes, berm depth and width, and stone size. For virtually all test conditions, a minimum wave reflection was found when the discontinuity (berm) depth was at one-quarter to one-half the water depth below the water surface. The overall wave absorption increased under the following conditions: an increase in horizontal berm width of up to five layers of stone; a decrease in the angle of the upper (stone-filled) slope when the berm depth is below one-fifth the water depth; and a decrease in the angle of the lower (impervious) slope when the berm depth is above one-half the water depth. The results should be useful where water wave reflections must be minimal and space is limited, such as in harbor walls or for hydraulic models.
DESIGN OF FILTER SYSTEM FOR RUBBLE-MOUND STRUCTURES
Authors: Lee Theodore T.
Published: June 2019

The rubble-mound seawalls, groins, breakwaters and ripraps around oceanfall pipelines are still the most common type of shore-protection structures currently in use. Major reasons include: easiness to construct and repair, flexible with respect to settlement, favorable wave-energy dissipation, fitness for any water depth and any foundation, and because of its economical nature if rubble-stones are readily available. However, the importance of a filter system in the stability of such structures must be emphasized. More recently, the submerged rubble-mound structures have become very popular due to aesthetic reasons. A filter system is considered a must to protect such a structure against erosion as a result of wave overtopping. Following a brief review of the problems, general discussions are made of the specific causes of failures including piping, overtopping, and nonstability. The physical factors that would affect the filter design are discussed in detail. Methods for design of filter system is presented including those applicable to the gradation of filter layers and to the plastic filters. The design procedure involves (a) making mechanical analysis of the backfill and base material, (b) estimating sizes of voids in the rubble-stones, (c) designing filter by Terzaghi criteria as revised by U.S. Army Waterways Experiment Station. A sample design of graded filter system behind rubble-mound seawalls is given. The procedure for the selection of plastic filters is also included. A comparison of the merits and demerits of these two types of filter systems will be made. This comparison will take into account the model test results conducted in the Look Laboratory. However, the readers are cautioned about the scale effects of the scour characteristics particularly on those tests with light-weight model sediments. This paper is intended as a general guideline for practicing engineers who will be responsible for design and construction of rubble-mound marine structures.
WAVE RUNUP ON VERTICAL CYLINDERS
Authors: Galvin C.J. , Hallermeier R.J.
Published: June 2019

Wave height at a point on vertical cylinders is measured as a function of the orientation angle, a, between the normal from the point on the cylinder and the direction of travel of a single periodic train of waves. The wave height distribution, H(a), has a broad maximum around a = 0° (facing into the waves) and a more restricted maximum at a = 180 . The maximum at a = 0° increases with wave height in all cases, and the super elevation has about the magnitude of the velocity head in the wave crest. In 21 different H(a) for which it is possible to determine the axis of symmetry by a simple objective test, 14 H(a) have axes of symmetry within * 3° of the direction of wave travel. Most of the variation in H(a) is due to variation in crest elevation; trough elevation remains relatively constant for the 360° range of a. The shape of H(a) depends more on height and cylinder cross section than on period, although the variation in H(a) as a function of cross section is significantly less than the extreme variations in tested cross sections. Applications of these results to wave direction measurement and to interpretation of wave records from surface-piercing wave gages are discussed.
SET-UP DUE TO IRREGULAR WAVES
Authors: Battjes J.A.
Published: June 2019

Energy losses in breaking irregular waves are estimated on the assumption that a wave, while breaking, loses only that portion of its height which would be in excess of the breaker height for the given wave period and the mean local depth. This leads to expressions for the magnitude of the radiation stresses as a function of the distance offshore. From this the variations in mean water level and the longshore current velocity are calculated with existing methods. Laboratory measurements of set-up in two dimensional irregular waves are described. The data appear to some extent to be internally inconsistent; this may be due to enclosed air bubbles.
REMOTE SENSING IN THE STUDY OF COASTAL PROCESSES
Authors: Magoon Orville T. , Pirie Douglas M.
Published: June 2019

The quantifiable determination of important coastal parameters remotely rather than by in situ measurements combined with automatic data reduction and analysis will result in a greatly increased understanding of the parameters being studied. This paper gives a progress report on joint Corps of Engineers-National Aeronautics and Space Administration (NASA) efforts to apply remote sensing in coastal studies. The devices used were multiband photography, the infrared scanner, the Side Looking Airborne Radar and various image enhancement and processing devices.
COASTAL ENGINEERING APPLICATIONS OF AERIAL REMOTE SENSING
Authors: Stafford Donald B.
Published: June 2019

aerial remote sensing techniques and provides a current state of the art summary of the utilization of aerial remote sensors in coastal engineering studies. The sensors' discussed include conventional black and white aerial photographs, black and white infrared aerial photographs, color and color infrared aerial photographs, multispectral aerial photographs, satellite photographs, infrared imagery, multispectral imagery, and radar imagery. The field of coastal engineering is considered in a broad context to include all important applications of aerial remote sensing that relate to coastal engineering problems. The use of remote sensors to monitor coastal changes, study coastal landforms, examine storm effects, map coastal areas, determine nearshore hydrography, and monitor the environmental effects of coastal engineering projects, a topic of considerable current concern, is described. The important characteristics of the various aerial remote sensors are described briefly. The advantages and limitations of the aerial remote sensing techniques for different coastal engineering studies are noted. The review and state of the art summary of the applications of the aerial remote sensors can be used by coastal engineers as guidelines in employing the sensors in future coastal engineering investigations.
COASTAL APPLICATIONS OF THE ERTS-A SATELLITE
Authors: Magoon Orville T. , Pirie Douglas M. , Jarman John W.
Published: June 2019

This paper describes the Earth Resources Technology Satellite (ERTS) placed in orbit in July 1972 and the ERTS simulation high altitude aircraft flights which have been flown for approximately one year. The ERTS satellite and simulation programs conducted by the National Aeronautics and Space Administration (NASA) have been developed to demonstrate the techniques for efficient management of the earth's resources. To achieve this objective the ERTS-A satellite provides for the repetitive acquisition of high resolution multispectral data of the earth's surface on a global basis. Two sensor systems have been selected for this purpose: a fourchannel multispectral scanner (MSS) subsystem for ERTS-A and a threecamera return beam vidicon (RBV) system. Systematic repeating earth coverage under nearly constant observation conditions is provided for maximum utility of the multispectral images collected by the ERTS satellite, which operates in a circular sun synchronous nearly polar orbit at an altitude of 494 nautical miles. It circles the earth every 103 minutes completing 14 orbits per day and views the entire earth in 18 days. The orbit has been selected so that the satellite ground trace repeats its earth coverage at the same local time every 18-day period within 20 nautical miles. A number of data output products are available from this satellite which include 70 mm products for precise location of topographic features, 9.5 inch positive or paper prints and also computer compatible tapes or punched cards. Also described are the results of the ERTS-A simulation flights flown at an altitude of 65,000 feet as related to coastal studies. Simulations of both the RBV and MSS in coastal areas are presented.
AN EVALUATION OP MIXING IN THE TAY ESTUARY
Authors: West J.R. , Williams D.J.A.
Published: June 2019

The authors consider the derivation of an expression for salinity distribution in an estuary, from an instantaneous mass balance equation for a solute in a continuum. The expression is compatible with existing field instrumentation and limited economic resources. Details are given of a prototype survey which included continuous monitoring of the salinity distribution of the Firth of Tay, an estuary subject to a wide range of fluvial and marine influences. The survey results enabled an apparent dispersion coefficient to be evaluated and an estimate to be made of the net mixing.
RESEARCHES ON THE DEFORMATION OF WAVE SPECTRA IN INTERMEDIATE WATER AREA BY CALCULATION
Authors: Wang Frederick L.W. , Ou Shan-Hwei
Published: June 2019

In order to devise more rational approach to predicat the wave features in intermediate water area, energy spectra in deep water area are to be changed to histograms, and every stripe of the histogram is to represent an elementary small amplitude wave. The deformation of such elementary waves over intermediate water area can be calculated theoretically by energy flux equation. Spectra in intermediate area can be worked out by summing up the wave energies deformed by shoaling, bottom friction and refraction. Calculation are carried out by computer. The peak of spectra will never change when it propagates from deep water to intermediate water area if the bottom contours are parallel to the shore line. Tangible process for using this approach to practical engineering problems is pending investigation.
USE OF MIXING TUBES ON MARINE OUTFALLS
Authors: Silvester Richard , Patarapanich Mana
Published: June 2019

To optimise dispersion from marine outfalls multiport diffusers have been developed. The addition of mixing tubes to such outlets can create an ejector action and so cause pre-mixing before discharge to the receiving mass of water. The characteristics of such water jet-pumps in this submerged condition have been derived elsewhere, but are applied herein to the dilution of effluents. For a range of jet to mixing tube area ratios optimisation has been carried out on a computer, thus indicating the densimetric Froude numbers and depth ratios at which dilution exceeds that for the plain jet. Even for a stagnant ambient medium dilution in experiments exceeds that predicted, possibly because of macro-turbulence not accounted for in the theory available. Turbulons developed in a mixing tube are larger than any emerging from a plain smaller jet and may thus promote better mixing from its exit to the sea surface. Mixing tubes have obvious applications in shallow water and where an effluent is particularly obnoxious.
HYDRODYNAMIC ANALYSIS OF SLUDGE DUMPED IN COASTAL WATERS
Authors: Edge Billy L.
Published: June 2019

Due to increased environmental pressures, there is a rapidly growing tendency to shift from traditional land disposal of dredged material to offshore or ocean disposal. The quantities of such materials are quite large, resulting in a very serious disposal problem. For example, maintenance dredging alone produces approximately six million cubic yards of material annually in Charleston Harbor. Existing techniques are reasonably adequate to describe the transport and settling characteristics of coarse, sandy dredge materials discharged from barges or hopper dredges at sea. However, such approaches need to be modified to describe the transport of fine-grained clay and silt materials. This material constitutes a significant portion of the dredged material resulting from both new harbor and channel construction and maintenance dredging along the coast of the Carolinas and Georgia. These fine-grained materials are subject to many additional physical forces as well as chemical phenomena, e.g., flocculation, salinity and temperature variations, etc. A hydrodynamic model for fine-grained dredged material has been developed which considers many of these forces. It is also applicable for describing the transport mechanisms associated with barge disposal of wastewater sludges from municipal and industrial sources. The results of the model indicate what discharge strategies are necessary for placing the sludge at a desired location or depth with a predetermined concentration.
REPRODUCTION OF PHYSICAL PROCESSES IN COASTAL AREAS
Authors: Ramming Hans-Gerard
Published: June 2019

Physical processes in the ocean, adjacent and marginal seas are mainly of special interest for oceanography and related sciences, whilst the knowledge and the understanding of these processes in coastal areas, estuaries and tidal rivers is also of significant practical importance for coastal engineers. Just measurements and observations are not sufficient to obtain a comprehensive insight into these processes and to explain and to understand the spatial and temporal states and their variations. Hydrodynamical~numerical investigations are delivering a considerable assistance. Within this paper my remarks will be restricted to some examples of the numerical reproduction of physical processes in shallow - water areas: 1) Dynamics depending on tides and wind; 2) Horizontal dispersion of suspended matter,, In concluding this Paper I shall mention a special coastal model with a permanent refined grid-net, which is a part of the wel] « known North Sea model.
A NUMERICAL MODEL FOR THE HYDROMECHANICS OP LAGOONS
Authors: Van de Kreeke J.
Published: June 2019

A numerical model is presented to describe the hydromechanics of lagoons connected to the ocean by relatively narrow inlets. Because special attention is given to the flushing, all second order terms in the hydrodynamic equations are retained. The study is restricted to lagoons with a onedimensional flow pattern and water of uniform density. In designing a numerical solution to the equations, the inlet equations are regarded as implicit boundary conditions to the equations describing the flow in the lagoon proper. The advantages of this approach are: (1) the size of the computational grid in the lagoon can be chosen independently of the relatively small dimensions of the inlets and (2) the flow at branching inlets (an inlet connecting a lagoon to the ocean such that branching of the inlet flow can occur) still can be described by a one-dimensional tidal model. The predictive capability of the numerical model is confirmed by favorable comparison between measured and computed particle paths and net transport for a series of laboratory experiments. In the experiments a canal of uniform width and depth is freely connected to a tidal basin at one end and at the other end is connected to the same basin by a submerged weir.
A MATHEMATICAL MODEL FOR SALINITY INTRUSION
Authors: Kuo A.Y. , Fang C.S.
Published: June 2019

A long term time-dependent mathematical model has been developed for predicting the salinity distributions in the upper York River System, including the tidal portions of the Mattaponi and Pamunkey Rivers. The method of calculating the longitudinal dispersion coefficient is discussed in detail. The study area and field project are described. The downstream boundary condition was found from a scheme combining a semi-explicit technique and linear extrapolation. The mass-balance equation, averaged over a tidal cycle and solved numerically by the implicit finite difference scheme, provided a reasonable solution and afforded economy in computer time. Field data were compared with the corresponding model results, indicating the general accuracy of the methodology.
ANALYTICAL MODELING OF ESTUARINE CIRCULATION
Authors: Fisher John S. , Ditmers John D. , Harleman Donald R.F.
Published: June 2019

A mathematical model is developed using analytical techniques to determine the longitudinal and vertical distributions of velocities and salinities, averaged over a tidal period, for mixed but partially stratified estuaries. The flow is assumed laterally homogeneous and the estuary width and depth are assumed to be functions of the longitudinal coordinate only. Required inputs to the model include the salt intrusion length, the ocean boundary salinity, the distribution of the ,depth-averaged salinity and the freshwater discharge. The governing equations included in the model are the vertical and longitudinal equations of motion, continuity, salt conservation and an equation of state. The key assumption is made that the longitudinal salinity gradient is independent of depth. This decouples these equations and thus permits an analytical solution to be found. Using data from laboratory flume tests and field surveys the model solutions are used to find correlations for the mean vertical transfer coefficients of mass and momentum with gross characteristics of the estuary. These correlations, plus the results from a one-dimensional numerical model, permit this analytical model to be used as a predictor of the velocity and salinity profiles in estuaries and to relate changes in freshwater discharge to possible changes in the location of shoaling zones.
DEFORMATION OF TIDAL WAVES IN SHALLOW ESTUARIES
Authors: Marche Claude , Partenscky Hans-Werner
Published: June 2019

Several mathematical models have been lately presented which describe the tidal wave propagation within an estuary. The existing models derived from the method for damped co-oscillating tides are based on sinusoidal wave profile. Meanwhile a tidal wave which moves upstream, generally exhibits a progressive deformation which tends to unbalance the length of time between flood and ebb tides. The actual profile is therefore no longer sinusoidal. Our investigation uses the potential method, and takes into account the wave amplitude which is usually neglected compared with the water depth. Finally, the velocity potential is obtained explicitely, using a double iterative method. Tidal elevation, particle velocities and trajectories are given by the same computer programmed algorithm. Our study shows that l) the phenomenon can be clearly visualized on the theoretical curves and 2) the magnitude of this deformation is inversely proportional to the water depth, becoming significant when the ratio f|/h reaches the critical value of 1/10. Damping and geometrical effects are also considered and the theory was applied to the St.Lawrence Estuary. A partial positive reflection of the incoming tidal wave is assumed at the narrow section near Quebec, whereas a complete negative reflection is assumed at the entrance to Lake St.Peter. The calculated and observed wave profiles, velocity distributions, and phase shifts are in good agreement.
TIDAL HYDRAULICS IN THE CANO MACAREO
Authors: Zagustin Konstantin , Masch Frank D. , Brandes Robert J.
Published: June 2019

Investigations have been undertaken to predict the tidal amplitudes and current patterns at the mouth of the Cano Macareo in Venezuela to the Atlantic Ocean. These studies were undertaken as part of a more comprehensive feasibility study sponsored by the Corporacion Venezolana de Guayana for location and orientation of a 60-foot deep navigation channel and for the design of related channel appurtenances. In the analysis, three simulation methods were employed conjunctively. These included oneand two-dimensional mathematical models and an electro analogical model. Model results have been supplemented with prototype data and other information based on field observations. Analyses provided for determination of tidal hydraulics, first, to establish baseline conditions as they presently exist, and second, to evaluate the effects of various proposed channel alignments. The twodimensional mathematical model and the electro analogical model both provided for inclusion of a pronounced longshore sea current which plays an important role in determining current patterns at the mouth of the Macareo. In addition, the use of a berm to modify the sea current in the vicinity of the channel entrance was investigated.
FIELD AND LABORATORY STUDIES; NAVIGATION CHANNELS OF THE COLUMBIA RIVER ESTUARY
Authors: O'Brien M.P.
Published: June 2019

A model of the estuary of the Columbia River was built and tested at the University of California, Berkeley, during the years 1932 to 1936, to study the effects of proposed changes in the navigation channels on the currents and sediment movement. The project was sponsored by the North Pacific Division of the Corps of Engineers, and the engineering results were reported at that time in internal memoranda. The basis for the selection of the scale ratios and other factors affecting the design of the model were reported in some detail (O'Brien, 1935), but only a brief note was published regarding the operation and the accuracy of the model (Johnson, 1948). In some respects this model is still unique, and a description of it may be of interest to the coastal engineers. This paper deals primarily with the model itself and not with the practical problems of channel maintenance and improvement, but some information regarding the regimen of the Columbia is necessary background for understanding the problems which were to be studied in the model. Figure 1 shows the configuration of the estuary, the jetties, and the ship channel. The river was then unregulated; the freshwater discharge exhibited an annual cycle with an average annual flow of 235,000 second feet, an average summer freshet discharge of 660,000 second-feet, and an average low-water flow of 70,000 second-feet. The tide shows a diurnal inequality, with the long run-out following higher high water; the diurnal range of tide is 8.5 feet, and the average range is 6.5 feet. Freshet flows affect the range and lag of tide in the river section above the estuary to such a degree that the published USC and GS Tide Tables were valid only for the months September through May and not for the freshet season. The range of tide is approximately constant from the ends of the jetties to Harrington Point; the lag over this reach is approximately two hours. At low river stages the tide is evident as far as Bonneville, 140 miles from the mouth; the tide wave progresses with steadily decreasing amplitude and there are no nodal points. The tidal prism varies both with range of tide and river stage; at low river stages, the prism corresponding to an 8 foot range is between 600,000 and 700,000 acre feet.
FLUSHING CHARACTERISTICS OF SMALL-BOAT MARINAS
Authors: Nece Ronald E. , Richey E.P.
Published: June 2019

Results are presented for a laboratory study Investigating the effectiveness of using a small-scale laboratory model to predict tidal flushing patterns in small-boat marinas. Laboratory results are compared with field measurements taken in an existing small-boat harbor. Model limitations are indicated, but it is concluded that simple, small-scale models can constitute an effective, economical tool in the evaluation of designs of small, enclosed basins where water quality problems associated with circulation patterns in the basin are important. Some implications are made concerning the effect of basin planform upon circulation patterns.
NEARSHORE CURRENTS SOUTHEASTERN STRAIT OF GEORGIA
Authors: Schwartz M.L. , Fackler R.C. , Hoeraut E.A. , Larsen C.E. , Lingbloom K.L. , Short M.A.
Published: June 2019

Nearshore water transport in the vicinity of Birch Bay and Cherry Point, Washington was investigated during the spring of 1971. The techniques used were: surface floats with variable depth drags, dye patches, streams of paper sheets, wind direction and velocity data, infrared and color aerial photography, and salinity and temperature readings from water samples. Birch Bay flood tide transports water into the bay, and ebb tide carries it out. The latter water either eddies off Point Whitehorn or moves out into the Strait of Georgia. Flood tide at Cherry Point transports water to the Point Whitehorn eddy or into Birch Bay, while on the ebb tide water moves from Cherry Point toward the vicinity of Neptune Beach and Sandy Point.
PROBLEMS OF OIL POLLUTION ON COASTAL WATERS AND BEACHES
Authors: Carow Uwe
Published: June 2019

In the coastal regions of the North- and Baltic-Seas of Germany more collisions with oil tankers have occured since 1955. These collisions have been followed by extreme pollution of the sea and coastal areas. In the following report the possibility of computing in advance the time and place of the landing of sludge, the advantages and disadvantages of chemical and mechanical treatment for the removal of the oil, the natural influences on the decomposition of the oil and the differences between oil pollution on coasts with tides and on coasts without tides are explained and critizised. Coastal areas and beaches are in danger of being polluted by oil. One part is the uncontrolled disposal of waste oil causing permanent pollution, the other part is the result of collisions with vessels. This danger is most threatening on much frequented shipping routes and in limited and relatively small sea-areas and bays of low depth, as it is the case with the North-and Baltic-Seas in the North of Europe.
NATURAL CLEANING OF OIL POLLUTED SEASHORES
Authors: Drapeau Georges
Published: June 2019

Field observations were carried out for a period of 20 months on the seashores of Chedabucto Bay, following the spillage of 108, 000 barrels of bunker C oil in the bay by the tanker Arrow in February 1970. The main factors that control the natural cleaning of seashores are as follows: 1) Physico-chemical characteristics of oil: The bunker C-type fuel oil carried by the tanker Arrow forms, when spilled at sea, a very stable emulsion containing some 40 percent sea water. The emulsion formed is 40 times as viscous as pure bunker C (30,000 poises at 32°F). 2) Nature of polluted seashore: The natural cleaning of seashores is essentially mechanical. Abrasion of oil is most rapid on sand beaches because sand-size sediments are moved more vigourously by wave action. Such beaches clean within six months. Cobble and boulder beaches take one year to clean in Chedabucto Bay. Bedrock outcrops are still covered with a veneer of "dried" oil after 20 months of exposure to the surf. 3) Hydrodynamics of the environment: Wave action is the dominant source of energy that reaches the seashores of Chedabucto Bay and the cleaning of beaches is directly related to the amount of wave energy reaching different areas of the seashore.
CONTAINING OIL SLICKS IN FLOWS OF FINITE DEPTH
Authors: Wilkinson D.L.
Published: June 2019

The hydrodynamics of oil slick containment are examined. It is shown that containment is only possible when a densimetric Froude number based on flow velocity and depth and the oil density is less than a critical value. Experiments confirmed that an oil slick was unable to maintain a stationary front when the Froude number exceeded the critical value. It is also shown that viscous effects ultimately limit the thickness and therefore the length and volume of any real slick. Expressions are derived which enable these limits to be determined.
TSUNAMI GENERATION AND PROPAGATION
Authors: Hammack Joseph L. , Raichlen Frederic
Published: June 2019

A linear theory is presented for waves generated by an arbitrary bed deformation {in space and time) for a two-dimensional and a three -dimensional fluid domain of uniform depth. The resulting wave profile near the source is computed for both the two and three-dimensional models for a specific class of bed deformations; experimental results are presented for the two-dimensional model. The growth of nonlinear effects during wave propagation in an ocean of uniform depth and the corresponding limitations of the linear theory are investigated. A strategy is presented for determining wave behavior at large distances from the source where linear and nonlinear effects are of equal magnitude. The strategy is based on a matching technique which employs the linear theory in its region of applicability and an equation similar to that of Korteweg and deVries (KdV) in the region where nonlinearities are equal in magnitude to frequency dispersion. Comparison of the theoretical computations with the experimental results indicates that an equation of the KdV type is the proper model of wave behavior at large distances from the source region.
SHALLOW WATER WAVE CHARACTERISTICS
Authors: Siefert Winfried
Published: June 2019

Prototype data from 24 wave stations on and around the tidal flats south of the Elbe estuary enable us to elaborate special shallow water wave characteristics, concerning the variations and correlations of heights, periods, lengths and velocities. This paper deals with some interesting aspects from the engineer's point of view. It turns out that the steepness factor - or H L -^o- of breaking waves is much smaller than of nong- T^ breaking waves and that steepness is no suitable parameter to describe a natural wave spectrum in shallow waters. On the tidal flats the maximum wave heights only depend on the depth of water, not on the steepness. Moreover the possible wave height proves to become much higher than theoretically predicted, especially in depths of water less than 2 m.
MAXIMUM BREAKER HEIGHT FOR DESIGN
Authors: Weggel J. Richard
Published: June 2019

A re-evaluation of previously published breaking wave data is used to develop a relationship for the maximum breaker height in terms of the depth in which the wave breaks, breaker steepness and the local beach slope. This relationship is used with the breaker travel distance equation of Galvin (3)* to estimate the maximum breaker height to which a coastal structure might be subjected. In addition, the range of depths in which a wave of given height will break is found by examination of the upper bound of observed values of dD/HD . An example problem is presented to illustrate the use of the general maximum breaker height design curves.
REFRACTION DE LA HOULE AVEC DIFFRACTION MODEREE
Authors: Biesel Francis
Published: June 2019

la methode "g£ometriquen de construction des epures de houle n'est qu'une approximation qui cesse d'etre applicable, par exemple, lorsque deux orthogonales se croisent. En effet, la regie de calcul de 1»amplitude donnerait alors utie valeur infinie au point de croisement, ce qui n'a eVidemment pas de sens physique. Pour traiter de tels cas, d'ailleurs frequents, il est indispensable d'utiliser une approximation meilleure, et pour cela de revenir aux equations fondamentales. Ceci est typique des problemes ou les effets de diffraction cessent d'Stre negligeables, cependant ceux-ci n'ont pas l1importance qu'ils prennent en presence de discontinuites brutales (contournement de l'extre'- mite d'une jete'e, par exemple). Nous disons done qu'il y a diffraction moderee. Ce que nous presentons lei est une methode de construction d1epures de propagation de la houle qui peut tenir compte de ce tifpe de diffraction. Cette methode a l'avantage d'etre une construction front d'onde par front d'onde, comme pour 1'approximation geometrique, mais les orthogonales ne peuvent plus Stre calculees independamment les unes des autres. Au total, le calcul est plus long, mais il reste cependant beaucoup moins lourd que les calculs de diffraction tenant compte e'galement des variations de profondeur.
A METHOD OF NUMERICAL ANALYSIS OF WAVE PROPAGATION APPLICATION TO WAVE DIFFRACTION AND REFRACTION
Authors: Ito Yoshiyuki , Tanimoto Katsutoshi
Published: June 2019

A method is presented to obtain numerically wave patterns in the region of arbitrary shape. The principle is to solve the linearized wave equations under given boundary conditions from a certain initial state. In this paper, two principal applications of our method of numerical analysis are presented in the fundamental fashion. The first application of our method is related to wave diffraction. The distribution of wave height along a semi-infinite breakwater and a detached breakwater is calculated and compared with that obtained from the conventional analytic solutions to confirm the validity of our numerical method. Three examples of application are presented to the wave height distribution along breakwaters of arbitrary shape and of arbitrary reflecting power and to wave force upon a large isolated vertical structure. The second application is to wave refraction. In particular, this method of numerical analysis is applicable to the analysis of wave propagation in the region of ray intersections which are indicated by the conventional geo-optic wave refraction theory. An example of application to a submerged shoal with concentric circular contours where a cusped caustics is formed is presented and the calculated wave height distribution around the shoal is compared with that obtained from hydraulic model experiments. Our method of numerical analysis might be applied to the calculation of wave height distribution in the region of more realistic bottom topography and it is possible to include vertical boundaries of arbitrary shape.
WIND-GENERATED CURRENT AND PHASE SPEED OF WIND WAVES
Authors: Shemdin Omar H.
Published: June 2019

Measurements of drift were made in a wind and wave facility at different elevations below the mean water level. The drift profiles were obtained for reference wind speeds, Ur = 3.1, 5.7 and 9.6 m/sec. The measurement technique involved tracing the movement of small paper discs which were soaked in water to become neutrally buoyant at the elevation of release. A logarithmic drift profile is proposed. The water shear velocity, U*w, predicts a surface stress, TS = pw U*S, in agreement with that obtained from the wind shear velocity, Ts = Pa U*li where pa and pw refer to air and water densities, respectively. The influence of wind on phase speeds of waves was investigated by solving the first order perturbation problem of the coupled shear flows in air and water. The air velocity profile was described by a logarithmic distribution and the drift profile was described by the proposed drift profile. Adequate agreement is found between the calculated and measured phase speed using Doppler radar in the wave number range 1.9 - 10 cm-1. In the wave number range 0.05 - 0.5 cm-1, measurements of phase speeds were obtained by using two wave gages. The waves were mechanically generated without wind and the wave gages were spaced to obtain coherent signals. The wind was then allowed to blow over the waves and the distance between wave gages was increased to maintain coherence. The wave length and frequency were obtained from the distance between the gages and from the generator frequency, respectively. The measured phase speeds were found to increase with wind speed consistent with theoretical computations.
VELOCITY AND SHEAR STRESS IN WAVE BOUNDARY LAYERS
Authors: Teleki P.G.
Published: June 2019

The critical force for the entrainment of sediment on the ocean floor is the maximum, instantaneous shear force. A numerical estimate for the stress is made from the third approximation of a second order boundary layer theory for oscillating laminar flow. The analytical derivation satisfies both the case of flow in an oscillating water tunnel and the case of a progressive (Airy) wave, where the shear distribution depends on the form of the velocity distribution in the boundary layer. Solution for the velocity is on the basis of iteration in an infinite series, where the convective terms are numerically evaluated from lower order solutions. For the boundary shear, the phase lead is found to be less than predicted by linear theory, and although the correction at the third approximation is small compared to lower approximations, the modified vertical distribution provides a basis for the correction of shear measurements, obtained by indirect means, to the boundary value.
FIELD OBSERVATIONS OF NEARSHORE CURRENT SYSTEM
Authors: Horikawa Kiyoshi , Sasaki Tamio
Published: June 2019

The two systems based on the principle of photogrammetric surveying have been developed in order to accomplish the field observations of nearshore current system induced by waves, and were applied to the field investigations on the Shonan Coast, Kanagawa Prefecture, Japan (Horikawa, Sasaki et al, 1970). The first is called as the Balloon Camera System and the other is the Synchronized Helicopter System. The main efforts were concentrated to the simultaneous observations of waves and current fields in and out the surf zone. Even there still exist some difficulties to be overcome in applying the present systems, the validity and usefulness of these systems were demonstrated by the obtained data. In this paper are presented the details of the developed systems and a part of the analyzed results by using the data obtained in field.
RIP - CURRENTS
Authors: Noda Edward K.
Published: June 2019

The generation and stabilization of rip - current circulation patterns is considered herein. An analytic model is developed to simulate the wave hydrodynamic processes in the nearshore zone, strongly influenced by the local bottom topography. The wave induced nearshore circulation pattern is computed and the results compared to prototype field data.
WAVES INDUCED BY NON-PERMANENT PADDLE MOVEMENTS
Authors: Moraes C. Campos , Ramos F. Silveira , De Carvalho M. Mendes
Published: June 2019

In a flume equipped with an irregular wave maker the motion of the paddle and the resulting waves may be thought of respectively as input and output of a system which, if linear, is for some purposes described by the so-called gain function. A theoretical and experimental study of this function is carried out ma king use of paddle movements that produce transient surface motion.
TIME-INTERVAL PHOTOGRAPHY OF LITTORAL PHENOMENA
Authors: Berg Dennis W. , Hawley Eugene F.
Published: June 2019

The collection of most data on littoral phenomena usually is based on the requirement of personnel and equipment actually being on-site for specific periods of time. An approach to minimize this requirement involves the use of a photographic technique, using time-interval cinematography. Two such systems have been used at sites in California; Point Mugu and Newport Beach. This method incorporates commercially available 16 mm motion picture cameras with automatic lenses, remotely programmed to shoot selected lengths of film at predetermined periods during a day, everyday. At Point Mugu the camera, housed in a weatherproof enclosure mounted atop an existing 100-foot tower, records shoreline conditions, wave characteristics and existing weather twice a day for a period of 20 seconds per exposure. The cameras are normally serviced on a weekly basis but are capable of longer unattended operation. To date this method has provided data which on preliminary anaylsis has revealed it to be of significant value for the purposes intended.
SEQUENTIAL PHOTOGRAPHY OF COASTAL WATER
Authors: Nichols Maynard M.
Published: June 2019

Sequential photographs from aircraft and satellites provide a source of data for studying dynamic features of coastal waters. Procedures for detecting features in sequential photos follow two approaches; (1) application of sequential signatures, (2) simple comparative analysis. For quantitative analyses images of two or more frames must have proper registration and comparable tones, i.e. tones free of photographic variance from film processing, varying exposure and solar illumination. After a normalization correction for variance is determined through use of density control points, density of successive frames is measured with a microdensitometer, the correction is a.pplied and tonal differences determined. Such differences relate to the time character of a feature and to causal processes. Application of correction values and numerical differencing is best accomplished in a digital or computerized densitometer. However, corrections and differencing can also be accomplished graphically from line traces or plots of an objective densitometer. Application of the procedures is demonstrated by analyses of tonal patterns of suspended sediment concentration in an estuary.
SEDIMENT TRANSPORT IN A TIDAL
Authors: Ritter John R.
Published: June 2019

Tidal flow and suspended-sediment discharge were measured in or near the inlet to Bolinas Lagoon through seven ebbtides and six floodtides. The highest flows and suspended-sediment discharges occurred during the major daily ebbtide. Most transported sediment was sand and most sediment deposited in the lagoon was sand. Computations from a relation of suspended-sediment discharge and tidal range indicated that the annual suspended-sediment discharge of ebbtides exceeded that of floodtides by 9,000 tons. The highest concentration of suspended sediment occurred near the east shore of the inlet, which is at the end of a sand spit. The measured volume of water moved by a tide ranged from 180 to 2,740 acre-feet and the maximum flow measured was 7,900 cubic feet per second. The highest average velocity for a measurement was 4.9 feet per second. The maximum average velocity in the inlet occurred within an hour after midtide during a floodtide and usually at about one-third tide during an ebbtide. The relation of average tidal velocity (ut) to tidal range (R), was ut = 1.21R'50°; the average flow for a tide can be estimated by multiplying this calculated average velocity by the average cross section of the inlet.
COASTLINE CHANGES NEAR A TIDAL INLET
Authors: Partheniades Emmanuel , Purpura James A.
Published: June 2019

Extensive coastline changes around the Ponce de Leon Tidal Inlet, Florida, are described, discussed and explained. These changes started developing immediately after the beginning of the construction of two jetties on both sides of the inlet forming part of a plan to stabilize the inlet, improve navigation conditions and bypass sand effectively. The mean annual littoral transport of sand was considered to be from north to south. Rapid sand accretion south of the south jetty started immediately after the beginning of its construction in 1969, reaching by November, 1971, a volume of approximately 1,400,000 cu. yds. Aerial photographs suggest that the sand was transported there from the south during the summer periods of northerly drift and from the offshore bar by refracted waves from the north. The accumulated sand is well protected by the south jetty during the winter storms from the northeast. Coastline and duneline recession occurred north of the inlet due, at least partially, to the described sand retention. It is concluded that for inlets where the littoral drift reverses its direction, the net annual rate of littoral transport is not a unique design criterion. Instead the total sand volumes transported annually in either direction should be considered.
MODELING SEDIMENTATION AT INLET AND COASTAL REGION
Authors: Lin Pang-Mou
Published: June 2019

Sediment transport In the vicinity of inlets and coastal regions depends on the combined bottom shear stresses due to both currents and waves. The modeling of the movement of bedload is controlled by the Proude law, bottom shear stress, wave steepness, and friction factor. Assuming Einstein's theory of bedload function can be applied to this study, an analysis was performed after conducting experiments in the flume and model basin. A series of results obtained from the flume tests is to Insure the relationship between the fluid characteristic and the movement of bedload. The final results concerning the longshore sediment transport appeared satisfactory with the estimated curves. The bottom configurations in the Inlet after each test were also shown satisfactorily similar. The sedimentologlcal time scale for the three bed materials were not In satisfactory agreement, however, more discussion of the results was presented in this paper.
LONGSHORE TRANSPORT OF SUSPENDED SEDIMENT
Authors: Fairchild John C.
Published: June 2019

In excess of 800 suspended sediment samples were collected from stations along the City Pier, Ventnor, New Jersey and Jennettes Pier, Nags Head, North Carolina using a tractor-mounted pump sampler. Most samples were collected within the surf zone at the Ventnor site. At the Nags Head site, sample collections included the surf zone, but generally extended over a wider range of the nearshore zone. Average sampling time was 3 minutes. Nozzle elevation varied from 3 inches above the bottom up to a maximum about mid-depth, generally not greater than 2.5 feet above bottom. Maximum concentrations at Ventnor ranged up to 2.6 ppt by weight and at Nags Head were about 4.0 ppt. Median size at Ventnor ranged from 0.12 to 0.15 mm and averaged about 0.20 mm in depths of 4 feet and less at Nags Head. Results are summarized in a series of scatter plots which relate suspended sediment concentration to nozzle height, wave height, water depth and sampling distance from an observed wave-breaker-line. Results are compared to CERC laboratory data, to two excerpted concentrations from unidirectional flow tests and to the CERC TR-4 design curve of longshore wave energy versus longshore transport.
MEASUREMENT OF SEDIMENT SUSPENSION IN COMBINATIONS OF WAVES AND CURRENTS
Authors: Jensen J. Kirkegarrd , Sorenson Torben
Published: June 2019

The paper describes a procedure for obtaining field data on the mean concentration of sediments in combination of waves and currents outside the breaker zone, as well as some results of such measurements. It is assumed that the current turbulence alone is responsible for the maintenance of the concentration profile above a thin layer close to the bottom, in which pick-up of sediments due to wave agitation takes place. This assumption gives a good agreement between field data and calculated concentration profiles.
PHASE DEPENDENT ROUGHNESS CONTROL OF SAND MOVEMENT
Authors: Inman Douglas L. , Tunstall Edward B.
Published: June 2019

Experiments with wave motion over asymmetrical "ripple-like" forms show that the difference between a net sand transport in a down-wave versus an up-wave direction is related to a subtle phase dependent mechanism associated with the intensity of vortex formation in the lee of the form. Artificial roughness modules have been developed, consisting of arrays of asymmetrical forms resembling natural ripples. The asymmetry of the forms causes an intense vortex to form in the lee of the steep face. This vortex traps and suspends sediment, which when the orbital motion reverses its phase, is lifted above the roughness element and carried in the new direction. Thus, the direction of the net sand transport is dependent upon the relation between the steep face of the roughness element and the phase of the orbital velocity; the net transport being in the direction of the orbital velocity that is out-of-phase with the maximum vortex formation.
SIMILARITY OF EQUILIBRIUM BEACH PROFILES
Authors: Paul M.J. , Kamphuis J.W. , Brebner A.
Published: June 2019

In the design of mobile bed coastal models it is inherently assumed that prototype beach processes may be modelled using lightweight sediment. At the Queen's University Coastal Engineering Research Laboratory, a long range project is currently in progress to determine scaling laws and scale effect for mobile bed coastal models. A large portion of this program is directly concerned with beach profiles and in this paper preliminary work is reported, in which a comparison is made between two dimensional laboratory beach profiles obtained from controlled "prototype", undistorted model and some distorted model tests.