bluuebunny/crossref_metadata_2025 huggingface dataset:
BEACH CHANGES AND WAVE CONDITIONS, NEW BRUNSWICK
Authors: McCann S. Brian , Bryant Edward A.
Published: June 2019

The coast line of Kouchibouguac Bay, New Brunswick, within the southern Gulf of St. Lawrence coastal province, consists of a barrier island system of sand beaches and low dunes. It is a relatively low energy system in a protected location with the important waves entering the bay through a narrow fetch window from the northeast. The behaviour of these wave trains and their refraction patterns within the S. Gulf of St. Lawrence and Kouchibouguac Bay were simulated by the construction of a series of refraction diagrams, from which it is possible to obtain a realistic appraisal of wave conditions at the shore. Waves entering the bay from N and NE directions are concentrated on the southern part of the barrier island system,, and those entering from the ENE and E are concentrated on the northern part. In greater detail, a series of wave refraction diagrams, based on former conditions of nearshore bathymetry at Richiboucto Inlet, help to explain the changes which have occurred there in the past 80 years. The simulation of wave behaviour in Kouchibouguac Bay has provided useful additional information which helps to explain the recent evolution of the barrier island system.
PREDICTING CHANGES IN THE PLAN SHAPE OF BEACHES
Authors: Price W.A. , Tomlinson K.W. , Willis D.H.
Published: June 2019

A mathematical model is described that is capable of predicting changes in the plan shape of a beach following the construction of sea defences or an alteration in the wave climate. The rate of change is calculated. The technique is illustrated by comparing model predictions with results from experiments carried out in a wave basin. The importance of the method in estimating coastal changes due to offshore dredging is mentioned, and the future development of the mathematical approach is outlined.
ON THE FORMATION OF SPIRAL BEACHES
Authors: LeBlond Paul H.
Published: June 2019

The theory of wave-induced longshore currents is applied to problems of beach erosion. An erosion equation is derived, relating the local erosion (or deposition) rate to the form of the beach and to the characteristics of the incoming wave field. A numerical integration technique of the erosion equation is discussed and a specific example is examined: that of a linear coast line which is gradually eroded into a spiral-shaped beach in the lee of a headland.
STATE OF GROIN DESIGN AND EFFECTIVENESS
Authors: Balsillie J.H. , Berg D.W.
Published: June 2019

An annotated bibliography on groins, compiled by Balsillie and Bruno (1972J, has provided the background for this paper. A review of functional design criteria is presented including groin length, height, spacing, permeability-adjustability, and orientation. A discussion of coastal processes and their relationship to groin design and effectiveness is" also given.
CALCULATED SAND FILLS AND GROIN SYSTEMS
Authors: Hale John S.
Published: June 2019

This paper demonstrates the results of the comparison between the calculated alignment of the beach's plan view end the actual alignment that resulted from the natural wave action. A new groin system was designed to replace an existing one, Th? new groin system and spacing ujas designed to hold the beach fill at the required width during average wave conditions as well as changing storm wave conditions. The system was designed for Las Tunas Beach, a beach near Los Angeles, California, In other words, the energies are tabulated for all storm conditions, and the beach alignment is recalculated for changing storm conditions. As the beach plan view alignment rotates back and forth with changing storm directions, it must always meet the minimum beach width requirements. This may entail changing the groin lengths, heights and spacing several times before the design complied with all requirements. Surveys from 1929 to 1970 showed that the beach did not have long periods., periods of several years, of constant ernsion or constant accretion. If there are no major man made changes, it is safe to assume that nature will provide an ad^ruate sand supply. L=s + , but not. least, the calculated beach alignments check with the empirical information gathered from years of survey;ng.
FIELD TESTS ON TWO PERMEABLE GROYNES
Authors: Price W.A. , Tomlinson K.W. , Willis D.H.
Published: June 2019

A section of beach on the south coast of England has been under surveillance for five years, from March 1966 until March 1971. During this period, two permeable groynes of the Makepeace Wood type were constructed. Beach cross sectional areas and rates of accretion were compared before and after groyne construction. The groynes caused a buildup in beach levels updrift.
SYSTEMATIC STUDY OF COASTAL EROSION AHD DEFENCE WORKS ITS THE SOUTHWEST COAST Of IKDIA
Authors: Moni N.S.
Published: June 2019

The SouthWest eoast of India is subjected to severe erosion due to attack by waves and. tidal overflow. Through the years the problem has intensified as beach front areas have become more extensively developed and subject to greater damage from the foree of the sea. More than 300 kms of the eoast is subjected to severe erosion due to constant attack by waves and tidal overflow, resulting in continuous recession, loss of valuable property and affecting many aspects of its economy* The paper presents the problem at the proper perspective. It deseribes the various physical factors of the Southwest eoast of India, namely the geomorphelogy, winds, waves, tides and currents, littoral drift, material characteristics, shore line and shore depth changes, effects of inlets and mudbanke. The study, evolution and development of different eeastal defense works and their behaviour and effectiveness is also presented.
LA PROTECTION DES PLAGES DU LITTORAL DU LAC SAINT-JEAN
Authors: Balvin Richard , Cousineau Yvan
Published: June 2019

Avant I' apparition des premiers am6nagements hydro-6lectriques de I'ALCAN, le nlveau du lac Salnt-Jean accusait des variations salsonnleres considerables. Aux peVIodes de grandes crues et d1 Inondatlons du prlntemps succSdalent les perlodes de basses eaux de la m!-4t6 qul donnalent lieu a de fr£quentes tempetes de sable et a la formation de dunes sur les berges. L'Implantation du barrage d'Isle-Maligne et I'eMargissernent des gorges des Grande et Petite Dgcharges, en 1924, permlrent de mtnimlser les dangers d'Inondation au prlntemps et de matntenlr en StS un plan d1 eau regularise1 dont devalent tlrer profit a la fols les exploltants des sites hydro-6lectrIques et de nos jours les estlvants et adeptes des sports aquatiques et nautiques. En contrepartle, le relevement du niveau moyen du lac eut pour effet d1 amorcer une eVoston des berges en prevision de laquelle I'ALCAN avait d'allleurs acquts les terrains en bordure du lac. Le littoral ayant attelnt, avec les ann4es, un nouvel Stat d'gquillbre, I'ALCAN a consent! a lalsser s'Stabllr, par vole locative, des chalets de plus en plus nombreux sur les terrains memes qu'elle avait acquis avant I' exhaussement du lac. Vers 1960, a la suite de la mlse en service de nouveaux am^nagements hydrauliques, les conslgnes'd'exploitation ont 6t6 modifies (le nlveau du lac Stant garde au volslnage de la cote maximale autor!s6e beaucoup plus tard en 6\6 et en automne) et les phSnomenes d'Erosion.
COASTAL SAND MANAGEMENT SYSTEM
Authors: Brush Birchard M.
Published: June 2019

Interruption of sand transport is the most persistent worldwide coastal problem. Wave action produces sand transport which is not a problem in some areas but in others results in coastal erosion, obstruction of harbor entrances, and permanent loss of sand. Conflict between saving sand and bypassing it is caused by a lack of methods to manage this valuable resource. Separate elements of control have been used with varying degrees of success; now it is proposed to incorporate subsystems into an integrated system for management of the littoral transport. A coastal sand management system is to be evaluated using three principal subsystems: (1) a mobile jet pump for use with a crater sink and fluidization accessories; (2) interlocking inertial modules which simulate structural materials because of high intergrain stresses; and, (3) the tactical deployment of phase dependent roughness elements to direct (or reverse) the net transport of sand. A coherent sand management system promises to make a start toward true control of littoral sand transport. In addition, there is the prospect of eventually establishing the first self maintaining harbors. It is attractive to consider systems which would be operative within reasonable cost, which may be entirely submerged, and which are capable of operating without regard to surface seakeeping problems. Some aspects of the system indicate possible use of the mobile jet pump as a means for estimating longshore transport in the field, use in archaeology, and as a dredging and maintenance tool for small nations whose investment capital could not support massive dredging operations.
PERIOD BY THE WAVE-GROUP METHOD
Authors: Thompson Warren C.
Published: June 2019

The wave-group period, T , is obtained by a eimple manual procedure from the periodic wave groupff'and sequences that appear in strip-chart records. A dozen or more values are commonly derived from a 20-minute record. When plotted as a time-series, T values form patterns that represent individual wave trains, each generated by a synoptic weather event. Swell trains and wind-wave trains can be distinguished by their characteristic period distributions. For swell trains, the mean wave-group frequency, f , obtained from the best-fit line to the time-series plot of f_ values (reciprocal T values), is equivalent to the frequency of maximum energy density, fm, obtained from spectral analysis. The distance and time of origin for a swell train can be determined from the time rate of change of f,,, and with the use of weather maps the generating area can be identified and the deep-water arrival direction of the swell train at the wave gage determined. The zero-line crossing period, T , represents an integration of the waves from all wave trains present and has no synoptic significance.
FAILURE OF SUBMARINE SLOPES UNDER WAVE ACTION
Authors: Mitchell R.J. , Tsui K.K. , Sangrey D.A.
Published: June 2019

The results of model tests, carried out to evaluate the stability of submarine slopes under wave action are presented. A Bentonite clay was sedimented in a glass walled tank 6 feet long by 0.5 feet wide by 2.5 feet deep. The sedimentation and consolidation processes were studied and sediment densities were measured at various depths in the profile. Vane shear strength profiles were also measured afvarious average degrees of consolidation. Plastic markers were placed in the sediment adjacent to a glass wall so that the soil movements under both gravity and wave induced slides could be documented by photography. Dimensional similitude is discussed and the model test data are presented in a dimensionless form. All instabilities were observed to be of the infinite slope type. Analysis of the data shows that wave action is instrumental in initiating downslope mass movements in gently to steeply sloping off-shore sediments. General lack of agreement between the model test results and published theoretical analyses was found but there was close similarity in the depths and form of failure under wave action and under gravity stresses alone. The loss of stability under wave action is analyzed on the concept that failure is gravity controlled and the soil strength is reduced to a value commensurate with gravity sliding by the cyclic shearing stresses imposed by progressive waves. A method of evaluating the stability of prototype slopes using a model test correlation and field vane strength measurements is proposed.
SEA-BED CONFIGURATION IN RELATION TO BREAKWATER STABILITY
Authors: Van Oarschat J.H. , Wevers A.
Published: June 2019

Stability tests on the Europoort breakwaters, situated on a shallow foreshore, clearly demonstrated the effect of the foreshore configuration on the overall stability. The present article gives a descriptionof the stability experiments and the interpretation leading to general conclusions regarding foreshore effects in combination with hydraulic conditions such as wave period, water depth and wave height. Both regular and irregular waves have been used. The experiments, carried out in commission of the Netherlands Government Department of Public Works (Rijkswaterstaat) were of an applied nature and were not directed primarily to the systematic study of foreshore effects.
ENGINEERING PROPERTIES OF SEA FLOOR SEDIMENTS FROM LA JOLLA CANYON
Authors: Noorany Iraj , Zinser Robert A.
Published: June 2019

Near surface sea floor sediments were obtained "by the tracked underwater -vehicle RUM from four locations on the floor of the La Jolla Canyon. The sediments were clayey silts of high plasticity. The engineering properties of the sediments, including grain size, index properties, strength and compressibility, were determined.
ESTABLISHMENT OF A COASTAL SETBACK LINE IN FLORIDA
Authors: Purpura James A.
Published: June 2019

The Florida Legislature passed a law in 1971 requiring the establishment of coastal construction setback lines on a county basis along the sand beaches of the State of Florida fronting on the Atlantic Ocean and the Gulf of Mexico. Florida's beach areas (valued in $ billions) are being developed at an accelerated rate, however the coastline is in a general state of serious erosion. These factors combine to make implementation of the above law extremely urgent. The Coastal and Oceanographic Department of the University of Florida has a contract with the Florida Department of Natural Resources to furnish a comprehensive engineering study of the various coastal counties of Florida in order to provide the technical information and make recommendations for the establishment of such setback lines. A typical coastal county study is described. The study included historical data related to shoreline stability, field measurements, computations and evaluation of all pertinent factors. Some factors considered were dune elevations, foreshore-offshore slopes, erosion trends, storm surge, vegetation bluff line, wave setup, uprush, coastal structures and upland development. Analysis of the pertinent factors resulted in formulation of criteria that were applied in recommendation of the setback line. The criteria application is described along with adoption procedures as required by law.
CHARACTERISTICS OF SALTATION OF SAND GRAINS BY WIND
Authors: Tsuchiya Yoshito , Kawata Yoshiaki
Published: June 2019

Although the phenomenon of saltation of sand grains in a sand storm is very complicated, there exists the successive saltation defined by the authors. The height and distance of saltation of sand grains in successive saltation by wind are compared with the theory of successive saltation proposed by the authors. The concentration of sand grains and velocity profile in a saltation layer are theoretically investigated with the aid of the results of experiment.
PRESSURE UPON VERTICAL WALL PROM STANDING WAVES
Authors: Shtencel V.K.
Published: June 2019

When surge waves approach a vertical wall a standing wave is formed ahead of the latter. This is the only case when the interaction between waves and structure result in a stable mode of motion with distinct kinematic characteristics. Such motion can be described by equations of hydromechanics without the introduction of any hydraulic coefficients; a comparison of various theoretical solutions with experimental data can serve as an additional criterion for evaluating the accuracy of this or that solution. The first theoretical solution for wave pressure acting upon a vertical wall under the effect of standing waves at a finite depth has been published by Sainflou in 1928 (1).
WAVE FORCE ON A VESSEL TIED AT OFFSHORE DOLPHINS
Authors: Goda Yoshimi , Yoshimura Tomotsuka
Published: June 2019

The solution of wave scattering by a vertical elliptical cylinder is

applied to calculate the wave forces exerted upon it. The wave forces in

the directions of long and short axes of ellipsis are shown in nondimensional

forms as the functions of the angle of wave approach, the diameter-to-wavelength

ratio, and the aspect ratio of ellipsis. The results of wave force computed

are also shown in terms of the virtual mass coefficients associated with the

reference volume of the circular cylinder the diameter of which is approximately

equal to the apparent width of the elliptical cylinder observed from the direction

of wave approach.

Theory is further applied for the wave forces acting upon a vessel moored

tight at offshore dolphins and the forces transmitted to the dolphins through

the vessel. The vessel is approximated with the fixed elliptical cylinder

having the same width-to-length ratio. The computation with directional wave

spectra shows that a tanker of 200,000 D.W.T. may exert the force of about

1,400 tons at the one-third maximum amplitude to each breasting dolphin when

the tanker is exposed to the incident waves of H,/,,=1.0m and T» / =10 sec from

the broadside.
STUDIES OF THE NAVIGATION BUOY FOR STRONG TIDAL CURRENTS AND LARGE WAVES
Authors: Nagai Shoshichiro , Oda Kazuki , Kurata Katsuhiko
Published: June 2019

Up to the present time, some researches have been done about hydrodynamic forces and tensile forces on mooring cables and configuration of cables in uniform and ununiform currents. Recently, the dynamic problems on the mooring system of buoy in waves are being studied by means of analytical and numerical methods. Authors have studied about a large navigation buoy exposed to strong tidal currents and large waves by means of model tests in an open channel and a wave tank.
WAVE FORCES ON A PLATFORM WITH A RIBBED BOTTOM
Authors: Denson Keith H. , Priest Melville S.
Published: June 2019

Observation of hurricane damage along the Mississippi Gulf Coast has stimulated studies of wave action on structures which permit the waves to pass beneath the floor or bottom surface. This paper reports a laboratory study which compares relative drag and lift forces on a structure with a plane, horizontal bottom surface to those on a structure with a ribbed bottom surface, for various conditions of relative wave height and relative clearance of the structure above the stillwater surface. Also, the effects of relative depth of ribs, relative spacing of ribs, and end webs or diaphragms are noted. The study was limited to the condition for which the bottom ribs were transverse to the general direction of wave motion. The results, which are presented in graphical form, clearly show the effects of the ribs.
FLUID FORCE ON ACCELERATING BODIES
Authors: Hamilton Wallis S.
Published: June 2019

The force exerted by a liquid on a moving body always depends on the preceding velocity and acceleration of the body. The Basset-Lai equation, derived from the linearized equation of motion, gives the force on spheroids when convective acceleration of the water particles may be ignored. Examples prove that the history integral it contains accounts for a large portion (even all) of the force. Measured forces on a cylinder anchored in accelerating water show that history is equally important when convective accelerations are large. An important unanswered question is whether history terms that will fit a range of motions can be invented for simple non-linear problems. For non-linear repetitive motion, such as the force exerted on piles by regular waves, no explicit history term is needed. The usual division of force into inertia and velocity portions is possibly less sound than a suggested alternative form from dimensional analysis. One cannot expect to unravel the hydrodynamics of irregular wave forces, but he may use similarity principles to predict their probability distribution from measurements made elsewhere. Irregular waves will be statistically similar, altho mean heights may differ greatly, if the probability distributions of suggested characteristics of the gage records are alike. Given similar waves and structures scaled to the waves, the probability distributions of dimensionless wave forces also will be alike, and the forces at one place can be predicted from measured forces at another.
MATHEMATICAL MODELING OF LARGE OBJECTS IN SHALLOW WATER WAVES AND UNIFORM CURRENT
Authors: Wang Hsiang
Published: June 2019

A mathematical model is presented which portrays the physical system of a large axially symmetric structure in a flow field of finite water depth, large amplitude wave and strong current. The flow field, which enters as the input, is derived from a velocity potential similar to that of the cnoidal wave of Keulegan and Patterson. The inclusion of a uniform velocity in the derivation of velocity potential results in a cross interference term in addition to the well known Doppler shift effect. The numerical results are compared with experiments on a bridge pier (Ref. 6) which is partially cylindrical with base diameter equivalent to 100 feet in prototype; close to the surface, where the wave action is greatest it is conical. These results are also compared with theoretical calculations based on linear wave theory and fifth-order wave theory. It is concluded that the results based on the modified cnoidal wave theory come closest to the experimental value.
INVESTIGATIONS OF WAVE-PRESSURE FORMULAS DUE TO DAMAGES OF BREAKWATERS
Authors: Nagai Shoshichiro , Kurata Katsuhiko
Published: June 2019

The wave-pressure formulas derived in our laboratory have been verified by the investigations of the slide of the vertical walls of composite-type breakwaters due to severe waves during heavy storms which have attacked numerous harbors in Japan since 1959. Some of the examples are shown in this paper.
FIELD MEASUREMENTS OF IMPACT PRESSURES IN SURF
Authors: Miller R.L. , Leverette S. , O'Sullivan J. , Tochko J. , Theriault K.
Published: June 2019

Field measurements were made of the vertical distribution of impact pressures exerted by breaking waves. Four distinct types are recognized and compared. These are near-breaking wave, plunging breaker, spilling breaker and post-breaking bore. The measurements were obtained by placing a 6 foot aluminum flat plate, backed by a cylinder in the surf zone, so that the fiat faced the approaching breakers. Five sensors were placed at one foot intervals on the flat. The sensors consisted of strain gage mounted aluminum diaphragms. Results indicated that impact pressure is significantly influenced by breaker type. The bore generated the largest impact pressures, followed in decreasing order by plunging breaker, spilling breaker and near breaking wave. In the vertical array, the largest impact pressures were recorded at or near the top, except for the bore where the reverse occurred. A qualitative explanation is given of various phenomena associated with impact pressures, by considering breaker mechanics.
CURRENT MEASUREMENTS USING A TILTING SPAR
Authors: Lowe R.L. , Inman D.L. , Winant C.D.
Published: June 2019

The dynamic response of the spar to oscillatory flow has been examined by modeling as well as computer analysis of the non-linear differential equation. Field measurements using the tilting spar have been made. These measurements are compared with theory and with other more direct measurements of the wave field. The tilting spar has been used to estimate wave direction. These estimates generally agree well with directional estimates made using a pressure sensor array and a two-component current meter.
WAVE TRANSMISSION THROUGH VERTICAL SLOTTED WALLS
Authors: Grune Joachim , Kohlhase Soren
Published: June 2019

This paper deals with the wave transmission through a vertical slotted wall. In an experimental study the transmission coefficient has been investigated as a function of the shape of the wall elements (rectangular shape and H-beam shape), of the ratio of solid wall to total wall length (wall-element ratio) and of the wave approach direction. The test results for a wave direction perpendicular to the wall are compared with previous investigations and theoretical derivations. For an oblique wave approach the test results are described by a semi-empirical formula. This formula, combined with a theoretical solution for perpendicular wave approach is used to describe the transmission coefficient for any angle of wave approach.
TRANSMISSION OF REGULAR WAVES PAST FLOATING PLATES
Authors: Sendil Uygur , Graf W.H.
Published: June 2019

Theoretical solutions for the transmission beyond and reflection of waves from fixed and floating plates are based upon linear wave theory, as put forth by John (1949), and Stoker (1957), according to which the flow is irrotational, the fluid is incompressible and frictionless, and the waves are of small amplitude. The resulting theoretical relations are rather complicated, and furthermore, it is assumed that the water depth is very small in comparison to the wave length. Wave transmissions beyond floating horizontal plates are studied in a laboratory wave flume. Regular (harmonic) waves of different heights and periods are generated. The experiments are carried out over a range of wave heights from 0.21 to 8.17 cm (0.007 to 0.268 ft), and wave periods from 0.60 to 4.00 seconds in water depth of 15.2, 30.5, and 45.7 cm (0.5, 1.0 and 1.5 ft). Floating plates of 61, 91 and 122 cm (2, 3 and 4 ft) long were used. From the analyses of regular waves it was found that: (1) the transmission coefficients, H /H , obtained from the experiments are usually less than those obtained from the theory. This is due to the energy dissipation by the plate, which is not considered in the theory. (2) John's (1949) theory predicts the transmission coefficients, H /H , reasonably well for a floating plywood plate, moored to the bottom and under the action of non-breaking incident waves of finite amplitude. (3) a floating plate is less effective in damping the incident waves than a fixed plate of the same length.
COMPUTER ALGORITHM OF WAVE RUNUP ON BEACHES
Authors: Wang Flora Chu , Purpura James A. , Chiu Tsao-Yi , Wang Yu-Hwa
Published: June 2019

An efficient computer program for predicting wave runup on beach profiles is presented. The solution is derived through the IBM 370/165 of the Computing Center, University of Florida. The wave runup data utilized in this study is based on the laboratory- derived curve obtained from the experimental work of Saville, and expressed as linear regression; the historical storm frequency data is furnished by National Oceanic and Atmospheric Administration; and the surveyed beach profile is supplied by the field program of Coastal and Oceanographic Engineering Laboratory, University of Florida. A broad spectrum of waves are selected to simulate hurricanes approaching the coast. The results thus obtained should provide useful guidelines in establishing the Coastal Construction Setback Line, and to the design criterion of Coastal Structures. i
WAVE SET-UP AND WAVE GENERATED CURRENTS IN THE LEE OF A BREAKWATER OR HEADLAND
Authors: Gourlay Michael R.
Published: June 2019

Field and model observations indicate the existence of wave generated currents in the lee of breakwaters and headlands. It is shown by an idealised laboratory experiment that such currents could be produced by an alongshore gradient of breaker height with wave crests parallel to the beach. The mechanism for the generation of the current is explained together with some of its characteristics including its interaction with the wave set-up which causes it,, It is further shown that it is possible to calculate by simple methods the hydraulic conditions causing the current. Currents produced by this mechanism appear to be of practical importance in determining the local plan shape of beaches close to breakwaters and headlands.
WAVE OSCILLATIONS IN AN OFFSHORE OIL STORAGE TANK
Authors: Raissi Hooshang
Published: June 2019

The rapidly incrasing demand to exploit known offshore oil fiojds throughout the world, ;md the costly conventional metiv d of pioii.'g the oil to the shore have given support to the concept of offshore storage terminals located ir. the immediate vicinity of uhe field. The Khazzan Dubai oil storage tanks at Fateh fi°ld, off- 3>>^..-e from Dubai (Chsmberlin, 1570), the Pazargad one milion-bbi crude-oil storage barge at Syvus field, Iran, offshore in the Persian Gulf (Feizy and McDonald, 1972'), and the nc offshore reinforcedconci'etc million-bbl oil storage tank at the Kkofisk field in the Kori-h Sei (C,,ean Industry, 1972), show the new attitude which the iffshore oil-production industry has developed toward UP1, system. A closed floating, or pile-supported, bottomless barrier migh* provide an effective solution for storing oil offshore or containing an oil spill. The crude oil coming from the production platform is injected at the sea level inside the closed bottomless barrier, it dispalces the water inside, and reaains above the water as a result of its density. The oscillations of the internal wave at the interfuc.-. o£ oil and water and the surface w:>ve2 resulting ?~rm dilrVrrtrtt incident waves in such, a container -v-./ie stv.Jieu in this work.
WAVE ATTENUATION AND CONCENTRATION ASSOCIATED WITH HARBOUR APPROACH CHANNELS
Authors: Zwamborn J.A. , Grieve G.
Published: June 2019

Modern bulk carriers require deeper and wider harbour entrances. As a result long approach channels have to be dredged outside the breakwaters. These large channels cause considerable changes in the waves due to refraction and diffraction which effect the wave conditions in the harbour entrance. As part of the Richards Bay harbour entrance studies, two phenomena were found to considerably effect the design of the entrance layout, namely: (i) wave attenuation for waves travelling near parallel to the channel axis, caused by refraction of wave energy away from the channel, and (ii) wave concentration on the channel side slopes, also mainly due to refraction, reaching a maximum for a critical approach direction of about 25 relative to the channel axis. As a result of the wave attenuation, waves travelling within an angle of 20 either side of the channel axis were found to cause no problems whatsoever with regard to wave penetration into the harbour. Unacceptable wave penetration was, however, experienced for wave directions close to the critical direction. A great number of variations to the entrance layout were tested to minimise this problem. The results showed the superiority of a flat channel slope of 1 in 100 above steeper side slopes and the beneficial effect of a Vee-shaped channel bottom. Also test results with irregular waves with regard to height, period and directions were found to be significantly different from those with uniform waves which considerably exaggerate the wave concentration phenomenon.
RESEARCH Of) THE MODEL SHELTERING INVESTIGATION OF A HARBOR
Authors: Hou Ho-Shuong
Published: June 2019

The Model Sheltering Experiment deals with the planning arrangement of the proposed harbor and is done by the worst wave condition (with respect to wave direction, wave height, and wave period) which probably occurred on the proposed harbor. The objectives of this experiment are to get the wave pattern of the harbor basin and to understand the various phenomena of the wave refraction, diffraction, and reflection caused by model test due to different harbor arrangement, and to comprehend the sheltering effect of the outer breakwaters. From the analysis of these test results, harbor planning of the most effective arrangement - the most economic length of breakwaters and the most ideal width of harbor entrance could be selected. For the purpose of analyzing results of model tests; comparison of theoretical wave diffraction calculation is proposed.
AMPLIFICATION OF LONG WAVES IN MARINA DEL REY
Authors: Lee Jiin-Jen
Published: June 2019

Water surface oscillations in a man-made marina--Marina del Rey, California--have been studied through prototype experiments and theoretical analysis. The prototype experiments are conducted by using both the floating gauge and pressure type gauge. The field data show that a distinct mode of oscillation with wave periods between 45 minutes and 50 minutes are naturally present almost all the time. Such resonant wave periods also agree well with the theoretical results.
THE LOSSES OF INNER ENERGY IN SEA WAVES
Authors: Shtencel V.K.
Published: June 2019

As it is known Lamb in his time suggested that energy losses in waves stipulated by liquid viscosity should be calculated by a formular: 2 W, = 2%2fZ \ V (1) .A where )) is kinematic viscosity coefficient The following prototype observations and laboratory experimental data showed that actual losses tens and hundreds times exceed those calculated by this formular. This can be explained by the turbulent character of according to Lamb, suggested to substitute the turbulent viscosity coefficient determined depending on wave parameters (instead of the kinematic viscosity one).
OIL SPREADING ON COASTAL WATERS
Authors: Kim Young C.
Published: June 2019

The area of oil spread was measured in the laboratory and the predictable model was established in determining the spreading area of oil on coastal waters. The relationship between the oil slick and the Reynolds, Froude, and Weber numbers was examined and the influence of wind, currents, and waves on the spread area was investigated. The effects on the changes in water depth and the alteration of the net spreading coefficient on oil spreading capacity were also examined. Comparison between the existing field measurements and the laboratory work was made.
EXCHANGE CHARACTERISTICS OF TIDAL INLETS
Authors: Taylor R.B. , Dean R.G.
Published: June 2019

Measurements of the exchange characteristics at tidal inlets are presented and interpreted in the framework of an idealized conceptual model. The conceptual model considers the primary cause of exchange to be the result of the differences in flow patterns away from and toward an inlet. The efflux from an inlet is considered to occur as a separated flow whereas a sink-type attached pattern is assumed for flow toward the inlet. The combined results of these two patterns is an effective lateral mixing. Field measurements were conducted from an anchored boat and a dye injection and monitoring approach were utilized. The measured results, expressed as "Basin Mixing Coefficients" are presented for three inlets and are interpreted in terms of the geometric and flow characteristics of the inlet and adjacent waters.
A THREEDIMENSIONAL MODEL OF A HOMOGENEOUS ESTUARY
Authors: Sundermann Jurgen
Published: June 2019

Basing on HANSEN's hydrodynamical-numerical method a threedimensional model of wind and tidally generated processes in a homogeneous estuary is developed. The model includes an arbitrary depth distribution and the simulation of a boundary layer near the bottom. Some numerical examples demonstrate the applicability for practical purposes.
FIELD AND MODEL DATA OF SPREADING IN ESTUARIES
Authors: Ohlemeyer F. , Berndt D.
Published: June 2019

The coastal regions in the highly industrialized zones of western Europe and other comparable parts of the world are a preferable field of new industrial settling. The economic reasons are: 1. Situation on deep water reachable by big vessels and 2. The increasing of the units of power plants and chemical industries demands for great quantities of water. For instance 200 up to 500 nf/s are no longer utopic today. Generally such great quantities are not available but in coastal regions especially on estuaries where the water movement is governed mainly by tidal action. Fig. 1 shows new industries and power plants in the region of the German Bay the shaded areas are consisting tidal models. In order to avoid environmental damages by pollution of industrial or thermal wastes and to diminish the recirculation effects of power plant, it is necessary to get correct information of the concentration rates resp. temperatures that will appear in these regions. The ways to get this information are well-known: 1. Direct measurements in prototype, 2. Mathematic models, 3. Hydraulic models or hybride models. Direct measurement is to some degree a necessary presumption to the latter two ways, but furthermore it afterwards gives information of the accordance of the model predictions. But often there is no money to do so. Of course it is not necessary to measure the whole area - that would mean model investigations scaled 1:1 - but some specific data will be sufficient.
THE EFFECT OF WIND ON CURRENTS AND DIFFUSION IN COASTAL SEA AREAS
Authors: Quetin B.
Published: June 2019

The calculation of turbulent flow using Navier's equations assumes the introduction of a turbulent viscosity coefficient the value of which is normally constant, conforming with Boussinesq's hypothesis. It was shown that setting aside this hypothesis, a velocity profile quite different to that resulting from the classic theory is obtained in the case of flow induced by wind. This result appears to be confirmed by the tests carried out in the Mediterranean. The advantage of this method is that it gives the vertical turbulent diffusion which is of particular interest to pollution studies.
FINITE ELEMENT MODEL OF TWO LAYER COASTAL CIRCULATION
Authors: Wang John D. , Connor Jerome J.
Published: June 2019

A set of "averaged partial differential equations for the circulation in a two layered coastal water is established by assuming each layer to be vertically homogeneous and by performing a vertical integration over the layer thicknesses. Since the phenomena to be investigated typically consist of long waves such as a tidal wave, the hydrostatic pressure assumption is also introduced. The finite element method is employed to transform the partial differential equations to a discrete system of ordinary differential equations which are solved using an implicit time stepping method similar to the trapezoidal rule, but with the variables (elevation and flows) staggered in time. A linear stability analysis shows the initial value problem to be unconditionally stable. In practice, instability due to boundary conditions and non-linearity sets in. Comparisons between computed and analytical solutions for simple cases give good agreement. The tidal excitation of Massachusetts Bay, represented as a rectangular basin with opening on one side is presented as an illustrative example.
HYDROTHERMAL MONITORING: SURRY NUCLEAR POWER PLANT
Authors: Fang C.S. , Parker G. , Harrison W.
Published: June 2019

A hydrothermal monitoring program has been designed and deployed to gather data on the temperature distribution in the tidal James River near the outfall of the Surry Nuclear Power Plant at Surry, Virginia, U.S.A. Monitoring to date has included two years of background data (1971 and 1972) taken prior to plant operation, and one year (19 73) of data with the plant in operation. The results of the first year post operational monitoring effort has been compared with the pre-operation background data and with the thermal effects that were predicted from studies by Carpenter and Pritchard on the James River Hydraulic Model at Vicksburg, Mississippi.
EFFECTS OF FLOODING ON A COASTAL PLAIN ESTUARY
Authors: Ruzecki Evon P. , Hargis William J. , Fang Ching S.
Published: June 2019

Rains from Tropical Storm Agnes resulted in unprecedented flooding of the Chesapeake Bay drainage basin in June of 19 72. A monitoring program was established to follow the effects of the flood in the Chesapeake estuarine system and contiguous continental shelf waters. Financial and logistic assistance was solicited and obtained from several federal and state agencies. The monitoring program, called "Operation Agnes" offered scientists a unique opportunity to watch the progress of the flood. Results of investigations into the effects of the flood show that salinity structure exhibited a four stage reaction, tides in the lower reaches of the estuaries were essentially uneffected and currents returned to normal after a short period of continuous ebbing. Total recovery of the salinity distribution was affected within one hundred days of flood crest at the fall line.
RESEARCH IN THE HARINGVLIET ESTUARY
Authors: Walther A.W.
Published: June 2019

After the closure of the Haringvliet estuary, part of the Netherlands Delta Project, morphological changes have occurred. Until now it was impossible to give a completely satisfactory forecast of such changes, however, with the aid of the Leendertse tidal computations a good picture of the tidal flow in the estuary can be obtained. In the paper a short description is given of both the tidal flow and the morphology of the Haringvliet estuary related with some problems of the practising engineers.
NEW METHOD TO CLOSE TIDAL RIVERS
Authors: Kniess Hans-Gerard
Published: June 2019

The closing of tidal rivers is still a risky project as the tidal flow alternates periodically its direction, velocity and level. On the last essential section of the Eider dam project a new method for closing tidal rivers was invented and successful operated. Contrary to common methods the main channel of the river was closed only by hydraulic placement of sand under protection of two permeable pile walls with perforated steel panels.
AERIAL PHOTOGRAPHIC WATERLINE SURVEY OF AN ESTUARY
Authors: SIndern J. , Schroder G.E.
Published: June 2019

The project of a "barrage across an estuary in Northern Germany was accompanied by a programme to monitor the hydrologic and morphologic situation. This became necessary in order to avoid dangers resulting from the sensitivity of the shallow wadden area to human interference. Various methods to record the morphology were tested. The aerial photographic waterline survey proved superior as it supplies a complete and economic record and allows accurate analysis of the topography. The principle consists in taking aerial photographs at short time intervals between low water and high water, each photo showing a different waterline. The scale chosen was 1:18000, corresponding to a flight altitude of 2700 metres. Rectification of the distorted photos requires reference markers to be distributed over the survey area which measures about 140 km^. By using simultaneous tide gauge records, contour lines can be constructed from the photographed waterlines. This morphologic record is supplemented by submarine survey of the estuary. It is expected that details of sediment transport and of tidal prism changes may be revealed. Predicted and actual effects of the barrage will be compared, which might lead to a better understanding of such coasts.
OPTIMAL DESIGN FOR WAVE SPECTRUM ESTIMATES
Authors: Tayfun M.A. , Yang C.Y. , Hsiao G.C.
Published: June 2019

Non-stationarity in an actual wave field restricts the application of the existing methods of estimating spectra. Despite the enormous amount of research work in the past, an analyst today is still faced with the lack of a unique procedure capable of providing a spectrum estimate which can be considered as the most accurate for the wave data collected under conditions where the stationarity assumption is in doubt. In this paper a generalized method is presented for estimating one dimensional frequency spectrum considering the non-stationarity. The generalized method and the associated design relations provide an effective measure for assessing the statistical quality of spectrum estimates, and a natural criterion as to how to select an optimal sample size. Concepts are illustrated by actual wave data analysis* and the validity of the procedure is demonstrated by simulation. In a simple manner, all concepts and methods developed for the non-stationary frequency spectrum apply to the wave number spectrum with spatial inhomogeneity. For simplicity, the presentation here will be primarily directed to the frequency spectrum.
SPECIAL CONSIDERATION ON THE DESIGN OF AN LNG HARBOR
Authors: Mehaute Bernard Le
Published: June 2019

One of the primary considerations in the design of an LNG harbor is safety, requiring berths to be separated by large distance and well protected from the outside wave agitation. Therefore, LNG harbors require expensive structures established as close as possible to the liquefaction plant (while crude tankers may be served by relatively much cheaper, single point mooring servers in deeper water). The cost of waiting time for the very expensive LNG ships has to be weighted against the cost of the additional berths and structures. (A 125, 000 m-^ LNG ships costs $2000/hour. ) The present paper describes the results of a study in which the optimum solution has been obtained by comparing these costs. The number of options is characterized by the number of berths. The cost to be added to the cost of construction of the berths includes an additional length of breakwater and additional dredging, plus the costs of financing during construction and the cost of maintenance. The waiting time for the LNG ship is generally determined, based on the classical Erlang formula for quelng theory. It is recalled that this formula is developed for an open loop. A closed loop theory has been specially developed for the present problem (since LNG ships will most probably operate between two well-defined harbors). The waiting times are 15 to 20% smaller than given by the closed loop theory. A comparison between single berth and double berth is examined. The effect of the rate of filling which is a function of the cryogenic pump capacity (or size of ship depending upon the dominating controlling factor) is analyzed. Finally, the sensitivity of the recommended solution as a function of the interest rates--examined in view of current economic uncertainties--is also investigated. The final recommendation for the design of the harbor, based on the prevailing factors, is the optimum economic solution.
QUANTIFYING SPOIL DISPOSAL PRACTICES
Authors: Halliwell Roy , O'Connor Brian
Published: June 2019

The results of an extensive field study undertaken in the Mersey Estuary and its approach channels are briefly described. These measurements were undertaken to obtain a quantitative understanding of the movement and circulation of water and sediment in the area. There is considerable dredging activity required in the area and the spoil from such operations is, at the present time, deposited at an offshore site in Liverpool Bay. A simple model is presented which attempts to quantify the movement of sedimentation and within the Mersey system. The field measurements showed that considerable quantities of sediment return to the docks, estuary and approach channels from the spoil ground. The model includes this fact and attempts to quantify the amounts returning to various areas. The model equations were applied to each year of the period 1955-65 to determine the various factors and to test its validity: this required the use of the annual hydrographic surveys and dredging records as well as the results of the field measurements. Finally, the model was used to compare the probable results of a number of possible schemes including re-siting of the spoil ground, pumping all dredged material ashore and free-dumping of dock dredgings in the estuary itself.
LABORATORY GENERATION OF WAVES OF CONSTANT FORM
Authors: Hansen J. Buhr , Svendson Ib A.
Published: June 2019

The paper reports measurements of waves generated by a piston type wave generator. The experiments show that for 0.10 < h/L < 0.65 the waves produced by a sinusoidal piston motion can be described as a second order Stokes wave superimposed by a free second harmonic wave. Results are presented for the height and phase velocity of the free second harmonic wave and compared with theories by Fontanet (1961) and others. Finally, the height of the free second harmonic wave is successfully reduced by a non-sinusoidal time variation of the piston motion, whereas addition of a rotation to the flap motion appears to yield only minor improvements.
A PROGRAMMABLE IRREGULAR WAVE GENERATOR
Authors: Webber Norman B. , Christian Colin D.
Published: June 2019

An account is given of the various design considerations in the development of a low-cost programmable wave generator for a laboratory channel. The ability of this equipment to reproduce prototype spectra is critically discussed.