bluuebunny/crossref_metadata_2025 huggingface dataset:
DENSITY CURRENTS AND TURBULENT DIFFUSION IN LOCKS
Authors: Halliwell A. Roy , O'Dell Martin
Published: February 2019

The paper describes a study of density-currents in locks where there is a net inflow of water into the dock The velocity profiles occurring are different than might be expected by simply superimposing the net flow onto a normal density-current profile The differences are shown to be due to the non-uniform salinity profiles occurring in the docks and a semi-theoretical study is presented which illustrates the importance of this salinity profile The accretion in the docks is explained by the transport of material into the docks during the levelling period The quantitative agreement between estimates based on measurements during the levelling period and the dredged quantities from the dock are good The locking operation is also shown to be an important factor in certain cases An attempt to describe the flow of silt into the dock using the onedimensional diffusion equation has shown that allowance must be made for the pick up of silt off the bed of the lock and the settling of silt (as the velocities drop) if quantitative agreement is to be obtained.
MEASUREMENT OP DENSITY CURRENTS IN AN IDEALIZED MODEL
Authors: Stuckrath Timm
Published: February 2019

The mixing of salt and fresh water in estuaries of tidal rivers is related to two major phenomenons turbulent diffusion and density currents The turbulent diffusion can be read off from the horizontal and vertical salinity distribution, the density current can be determined from the velocity distribution on the vertical axes The physical description of tidal mixing in a mathematically closed system is not possible, because turbulent diffusion and gravitational convection are varied by such different influences as tidal action, fresh water flow, river bed form and roughnes, and gravitational and CORIOLIS forces Most research in this field has been done on turbulent diffusion, especially to predict the mean horizontal (longitudinal) salinity distribution IPPEN, HARLEMAN (ref 11, 12), and others have found out by various model tests that PICK'S law of diffusion used in one-dimensional form is a good physical description for the longitudinal salinity distribution and that the tidal energy dissipation, the cross section, and the fresh water flow are a good means of classifying tidal estuaries from the viewpoint of stratification.
COMPUTATION OF STORM SURGE
Authors: Silvester Richard
Published: February 2019

From knowledge of wind resistance coefficients measured over the sea, it is possible to compute the shear stress of a wind field on its surface Where a body of water is relatively shallow, such a shear stress will transport water to the downwind end and so create a high water level or surge Graphs are presented for ready application of the relevant formulae to cases of lakes and Continental Shelves The wind fields of either uniform or triangular horizontal distribution in velocity are included, as well as conditions of stationary or moving fetches Surges from seven typhoons travelling towards Hong Kong are computed and compared to actual records.
ANALYSIS OF HURRICANE TIDES AT PADRE ISLAND, TEXAS
Authors: Masch Frank D. , Brandes Robert J. , Hill Floyd R. , White William A.
Published: February 2019

To establish design data, a study was undertaken to determine expected hurricane tide elevations, durations and frequencies of occurrence for events of various magnitudes in the vicinity of a proposed development at Padre Island, Texas A set of synthetic hurricanes with selected sizes, translation speeds, wind fields, and pressure patterns were generated corresponding to various frequencies of occurrence of the CPI Two numerical computer models were developed to determine the offshore surge hydrograph and to route the surge through the bay waters for each synthetic hurricane moving directly over the site Results included storm tide hydrographs at selected locations near the development Synthetic storms were also routed across the coast at locations north and south of the site and storm hydrographs again computed.
JAMAICA BAY HURRICANE BARRIER
Authors: Panuzio Frank L.
Published: February 2019

A 12 4 mile beach erosion control and hurricane flood protection project includes Jamaica Bay and the Rockaway Inlet in the southwest corner of Long Island, New York«i The project would provide 6 1 miles of beach fill and floodwalls along the Atlantic Ocean shore and 6 3 miles of inland structures to tie back to high ground, including a 0 9 mile barrier across the inlet The barrier, with a 300 foot gated opening and a 300 foot ungated opening, would permit suppression of the design hurricane surge so as to eliminate the need of flood protection works within the bay Linear mathematical models were used to determine these openings Because of the limitation of these models to produce adequate data m the bay pertinent to environmental and ecological considerations, three hydraulic models were utilized General conclusions drawn from the hydraulic model test data are that the results of the mathematical models were upheld, a design storm with high peak is critical for determining the height of protection, a design storm with high volume rather than high peak plus rainfall runoff is critical in determining ungated openings and suppression of bay levels, and there is a combination of gated and ungated openings that would meet the flood protection, navigation, environmental and ecological objectives.
TIDAL WAVES IN SCHEMATIC ESTUARIES
Authors: Vollmers Hans , Sunderman Jurgen
Published: February 2019

An investigation of tidal waves in schematic estuaries has been carried out simultaneously for hydraulic and hydrodynamic- numerical (HN) models Thereby a far-reaching agreement of results is obtained for geometrically simple shapes. In these cases hydraulic investigations can be replaced equivalently by HN-computations.
COMPILATION OF OCEAN AND LAKE WAVE STATISTICS
Authors: Hale John Simpson
Published: February 2019

The wave program described in this paper is one intended to provide wave statistics by having our Los Angeles County life guards observe the wave heights, directions and periods. Mark-sense cards and high speed data processing equipment and computers are used to handle the volumes of statistics. While some scientists are planning very accurate, costly solutions to the problems of wave statistics, agencies are reluctant to venture into an expensive, elaborate wave surveillance program requiring a large quantity of personnel. I feel that neither the accuracy of present day design or construction methods warrant "split hair" accuracy in wave surveillance. The method described in this paper will provide a practical solution if the statistics are handled as follow 1. Wave statistics are gathered continuously over many years of time. 2. A standard is set to check the observed values. 3. Large rare damaging storm conditions will be developed by any reasonable means available until enough years of observation have passed to provide adequate statistics.
DEFORMATION OF ROTATIONAL TIDAL CURRENTS IN SHALLOW COASTAL WATER
Authors: Gohren Harold
Published: February 2019

Along gently sloping coasts of seas having rotary tidal currents, the symmetry of the rotary current is interrupted where the water is shallow As a result, residual counter currents are formed The dynamics of such a current system are described based on current measurements in the Elbe Estuary (southeastern North Sea) The residual currents of this area result in the movement of bottom sediment and are most likely responsible for a series of similar appearing morphologic features.
HARBOR STUDY FOR SAN NICOLAS BAY, PERU
Authors: Keith James M. , Murphy Emmett J.
Published: February 2019

A pair of ducted impeller current meters, one mounted vertically and the other horizontally, were used to measure wave action at San Nicolas Harbor, Peru The horizontal water velocity records are superior to conventional wave records because they measure directly the wave property which induces adverse horizontal ship motion, and provide directional wave data Spectral analysis methods proved well-suited to detailed interpretation of the particle velocity records, while considerable insight into the wave phenomena was gained by simple, rational inspections and interpretations of the records Time-lapse movies of a moored ship, when correlated with simultaneous water particle velocity records, provided an exceptionally clear picture of ship response to wave action, and led to the rather surprising observation that long-period ship motion is not necessarily caused by long-period waves The foregoing ship response was duplicated in hydrau1ic model tests.
SURFACE OSCILLATIONS IN A WATER TANK CAUSED BY A SUBMERGED JET
Authors: Font Juan B. , Azpurua Omar , Aranguren Flora
Published: February 2019

In this paper are studied the surface oscillations that form m a water tank when a jet emerges fron the botton The experimental systen consisted of a circular water tank with the water intake at the bottom close to its cj.rcunference Surtace osci_ nations were recorded for different situations lhe experirental results are presented in both dimensional and dirensionless ploltmgs where the oscillations atrplitud is related with water depth and jet diameter and velocity The dimensionless graphs show that the oscillation amplification is, within the variables ranges studied, mostly independent of tank diameter.
EFFECT OF LONG PERIOD WAVES ON HYDROGRAPHIC SURVEYS
Authors: Magoon Orville T. , Sarlin William O.
Published: February 2019

In conjunction with routine hydrographic surveys at Santa Cruz Harbor, California, bottom elevation discrepancies were observed which were not associated with positional errors It was suspected that these errors were associated with long period wave activity, common at this particular location on the Pacific Coast The existing practice for obtaining hydrographic soundings is by use of floating craft using either echo sounding techniques or a "lead line " Both of the above techniques utilize the instantaneous water surface at the survey boat as a datum reference Normally the water surface elevation is determined by use of a water level recorder Based on the analysis of 50 repetitions of a well monumented cross section in Santa Cruz Harbor, it was concluded that long period waves affect the results of hydrographic surveys by slowly varying the datum plane In the case of Santa Cruz Harbor, the maximum error due to this effect would be about +15 feet.
SELECTION OF DISPOSAL AREAS FOR SPOIL FROM BALTIMORE HARBOR
Authors: Hoffman John F.
Published: February 2019

Selection of sites for the diked disposal of 100 million cubic yards of spoil dredged from Baltimore Harbor presented a formidable problem Fifty percent of this spoil will be derived from harbor improvement m the next ten years The remainder will result from maintenance dredging and some private dredging over a 20 to 25 year period The number of sites available for diked disposal areas, the various methods used for dredging and the fact that the dike material required transportation to site gave rise to a number of variables The decision making process was facilitated by an econometric model Concentrations of metals such as chromium, cadium, zinc, lead, and copper have been found in the sediments of Chesapeake Bay An investigation as to the mode of their occurrence m the material to be dredged was made to appraise any possibility of toxic concentrations occurring m filter feeders such as oysters for shellfish constitute a sizeable industry in the Chesapeake Bay Stabilization of the deposited dredged spoil was investigated m order to determine whether the unstable loosely-deposited fine gram material extending over a three to five square mile area could be economically converted to a firm foundation material suitable for industrial parks, harbor terminals or water-oriented parks.
MACRO-TURBULENCE FROM WIND WAVES
Authors: Lee Chin-Yuan , Masch Frank D.
Published: February 2019

Laboratory studies m a wind wave flume were carried out to investigate the macro-scale turbulence associated with wind waves and white cap conditions Velocity fluctuations m water were measured with a hot film anemometer and parametric correlations between wind waves and turbulence characteristics were established Measured data were recorded m analog form, digitized and stored on magnetic tape Auto - covanance functions and power spectral density functions were then obtained for all sample records Results showed that the depth of the penetration of the macro-scale turbulence increased rapidly with wind speed but the rate of penetration diminished at the higher wind speeds This rate of macro-turbulence penetration was found to vary inversely with wave height and wave steepness Most turbulent fluctuations having frequencies equal to or higher than the frequency of the ambient surface waves were confined to the zone of macro-turbulence penetration although some disturbances such as vortex rings and other turbulence associated with white cap wave conditions occasionally penetrated to greater depths It was found that the energy dissipation increased with wave height and that almost all wave energy dissipation was concentrated near the water surface.
ENERGY TRANSFER MECHANISM FOR FINITE AMPLITUDE WAVES
Authors: Zagustin Konstantin
Published: February 2019

A basic mechanism is proposed to explain the growth of finite amplitude water waves due to the effect of normal stresses. The proposed mechanism can probably be applied to the whole range of wave's growth, starting from a small amplitude wave up to the case of a limiting and breaking wave condition. The transfer of energy from air flow to the water wave is explained by the existance of a circulation flow pattern above the water surface, which is responsable for a phase-lag of the normal stress distribution in relation to the wave's profile. Such a circulation flow pattern extends throughout the whole wave length and it is quite different from the classical concept of flow separation, as postulated by Jeffrey's. The difference becomes as a result of considering a different boundary condition at the interface. Experiments performed on wavy models with moving boundary conditions, for small amlitude waves and finite amplitude waves showed that the normal stress distribution is similar in both cases, and displays a noticible phase-lag with respect to the wave's profile. It was observed that for both cases a circulating flow pattern was present above the water surface, which indicated some relation between the flow vorticity above the wave and the normal stress distribution. To prove the role of circulation in the energy transfer mechanism, a model was built with water and mercury as working fluids. In this model the interface was initially non disturbed, when both fluids move in opposite directions. However, when a forced circulation was applied by means of a variable speed rotor located above the interface, a wave would form. The wave would be inicially of small amplitude, but with an increase of circulation would become of finite amplitude, then reach the angular crest condition and finally would reproduce the breaking condition at the crest. The obtained experimental results proved the importance of the circulation flow pattern present above the wave surface, and suggest that a mathematical model could be formulated based on vorticity analysis, which would be able to provide an explanation for the energy transfer mechanism due to normal stresses at all stages of wave's growth.
TURBULENT CURRENTS IN THE PRESENCE OF WAVES
Authors: Lundgren Helge
Published: February 2019

This paper presents an approximate theory for the reduction of the velocity of a current due to the presence of sinusoidal waves. For a given slope, S, in water of constant depth, d, the current velocity profile is U(z) = U^ (2.5'ln - - A) (1) t zo as a function of the height, z, above the bed. Eq. 1 is valid only above the thin wave boundary layer near the bed, the roughness of which is k = 30 z . Uf is the current friction velocity defined by p Ul = y d S = T (2) f ' cw CW Values of A can be found from: Fig. 2 where Aj applies when the direction of wave propagation is parallel to the current direction, and Fig. 3 where A2 applies when the direction of wave propagation is perpendicular to the current direction, cf. Notation in Sec. 2. The theory is based upon a number of assumptions (see Sec. 4).
HORIZONTAL WATER PARTICLE VELOCITY OF FINITE AMPLITUDE WAVES
Authors: Iwagaki Yuichi , Sakai Tetsuo
Published: February 2019

This paper firstly describes two methods to measure vertical distribution and time variation of horizontal water particle velocity induced "by surface waves in a wave tank These two methods consist of tracing hydrogen bubbles and using hot film anemometers, respectively Secondly, the experimental results by the two methods are presented with the theoretical curves derived from the small amplitude wave theory, Stokes wave theory of 3rd order, and the hyperbolic wave theory as an approximate expression of the cnoidal wave theory Finally, based on the comparison of the experimental data with the theoretical curves, the applicability of the finite amplitude wave theories, which has been studied for the wave profile, wave velocity, wave length and wave crest height, is discussed from view point of the water particle velocity.
AIE ENTRAINMENT AND ENERGY DISSIPATION IN BREAKERS
Authors: Fuhrboter Alfred
Published: February 2019

Even m shallow water, only a part of wave energy is lost by turbulent viscosity and bottom friction, most of wave energy transfer takes place m the narrow zone of surf at the shore. Till to the point of breaking, the theoretical conception of an one-phase flow may be applied to the problem. From beginning of breaking, however, the effect of aeration can not be neglected. Prom a simple physical consideration, the sudden reduction of wave height and wave energy inside the surf zone can be explained by the entrainment of air bubbles into the water. Except compression and surface tension effects, most of wave energy is stored at first by the static energy of the air bubbles which are driven into the water. Using idealized assumptions for calculation (uniform concentration of air bubbles a.s.o.), it can be shown that m a plunging breaker the wave energy is dissipated on a very short way (less than on wave length), for a spilling breaker however, this way is of the order of some wave lengths.
THE DEVELOPMENT OF UNDULAR BORES WITH FRICTION
Authors: Hawaleshka O. , Savage S.B.
Published: February 2019

A theoretical and experimental study of the initial development of undular bores in two-dimensional, rectangular channels with and without boundary friction was performed Equations similar to those of Boussmesq, but including higher order and wall friction terms are presented and solved numerically by an implicit finite difference method A Pohlhausentype boundary layer momentum integral method is used to obtain the wall shear stress distribution under a developing long wave from the consideration of the boundary layer underneath it The solution is performed in a quasi-iterative manner proceeding from the friction coefficient calculation for an initially assumed wave profile to the inclusion of this coefficient in the calculation of a new wave profile at an advanced time Comparisons of theoretical and experimental results are given For the initial development of the undular bore with which the present work is concerned, the measurements are found to be m reasonable agreement with the theoretical predictions The effect of the wall shear stress manifests itself mainly in a slight reduction of the wave amplitudes.
COMPUTER MODELLING OF DIFFRACTION OF WIND WAVES
Authors: Fan Shou-shan , Borgman L.E.
Published: February 2019

A digital computer model for diffraction of wind waves behind a breakwater is developed The model combines the hydrodynamic theories and the concept of directional spectra It is designed so that it may be used not only for the study of the wind wave diffraction problem behind breakwaters but also for the investigation of experimental (or field) data analysis procedures of other kinds An extensive study of optimum data length, lag number and gage spacings m wave gage arrays is presented.
SWELL AND STORM CHARACTERISTICS FROM COASTAL WAVE RECORDS
Authors: Thompson Warren C.
Published: February 2019

Manual analysis of strip-chart records from a conventional wave sensor at Monterey, California was found to yield a linear frequency shift associated with each arriving swell tram, from which the origin time and travel distance of the swell could be computed The use of surface weather maps allows identification of the source, and thereby yields an accurate determination of the deep-water arrival direction of the swell for use on the local coast The wave records are analyzed for the frequency of the individual waves composing wave groups, f , consistency of the results obtained indicates that f is equivalent to the frequency of maximum energy density f , obtained by spectral analysis Five swell sets studied were found to max J f J originate in North Pacific storms advancing toward Monterey The seas in the fetch were fully arisen at the time of computed swell origin, and the surface to geostrophic wind ratio was 0 83 The dominant swell emerged from the fetch at a time when its group velocity equalled the velocity of the fetch toward Monterey.
INTERACTION BETWEEN WAVES AMD CURRENTS
Authors: Jonsson Ivar G. , Skougaard Christian , Wang John D.
Published: February 2019

This paper presents some theoretical results of a general study of the interaction between surface gravity waves and a steady current Assuming irrotational flow and a second order Stokes wave motion, the main objects of the paper have been a To present a simple graphical method for the computation of the wave length m a current field b To introduce the concept of the mean energy level for a periodic wave motion with a steady current superimposed c To utilize this for the calculation of the "current-wave set-down" for a two-dimensional motion with a constant discharge over a gently sloping bottom d To present a complete set of conservation equations for the case considered under point c e To present graphs and tables for the variation in length and height of wave for the case considered under point c No experimental results are presented.
A HIGHER ORDER THEORY FOR SYMMETRICAL GRAVITY WAVES
Authors: Monkmeyer Peter L.
Published: February 2019

A higher order theory is presented for symmetrical, non-linear gravity waves As a consequence of the generality employed, the theory includes the full range of possible wave lengths, water depths and wave heights that may be encountered, and brings them into one unified formulation Thus, the theory encompasses both linear and non-linear waves, including Airy waves, Stokes waves, cnoidal waves and the solitary wave Based on the work of Nekrasov, a complex potential in the form of an infinite series is developed to describe the flow field The potential satisfies the bottom (horizontal) condition as well as the kinematic surface condition exactly Furthermore, the dynamic surface condition is satisfied by numerical calculation of the series coefficients which appear in the complex potential The calculation of these coefficients is accomplished by solving a set of non-linear algebraic equations, with the aid of a Newton-Raphson iteration procedure and matrix inversion Coefficients of the complex potential have been obtained for a fifth order analysis and preliminary results are presented in tabular form A brief discussion of the characteristics of the waves, including wave speed, wave shape and the height of the highest possible wave follows.
DIMENSIONAL ANALYSIS - SPURIOUS CORRELATION
Authors: Yalin M.S. , Kamphuis J.W.
Published: February 2019

The theory of dimensions has been subject of considerable controversy and only in the last few decades has it been agreed that dimensional methods can serve as a powerful tool m experimental investigations of physical phenomena Its effectiveness becomes especially noticeable when the number of factors involved is large and the theoretical knowledge is insufficient However, like any other mathematical tool, the theory of dimensions can supply correct and useful results only if it is properly applied One example of improper application is the introduction of an exaggerated and sometimes simply of a nonexistent correlation between the experimental results The purpose of the present paper is to analyse these kinds of spurious correlation.
REACH OF WAVES TO THE BED OF THE CONTINENTAL SHELF
Authors: Silvester Richard , Mogridge Geoffrey R.
Published: February 2019

The physiography of Continental Shelves and their major composition of sediment indicate strongly their terrigenous origin and their smoothing by wave action This premise is supported by the geologic time over which waves have existed and the mass-transport velocity in these relatively shallow depths, particularly the net movement within the wave boundary layer at the bed A given wave tram arriving obliquely to the shore can transport material along the coast, both beyond the breaker line and within the surf zone It is shown that for equal over-all discharge in the two zones, the average sediment concentration offshore close to the bed need be reasonably small, indicating that transport near the beach could be a fraction of that from the breakers to the reach of the waves This latter limit is shown to extend at least half way across the Shelf, with possibilities of greater reach when more realistic prototype conditions are introduced into experiments.
OBSERVATION OF SEDIMENTMOTION BY UNDERWATER-TELEVISION
Authors: Luck Gunter
Published: February 2019

For observation and interpretation of sedimentological movements an Underwater Television set-up is employed, which is discribed in the following paper. The so long achieved results and experiences are exemplified.
THE HISTORY OF THE DUTCH COAST IN THE LAST CENTURY
Authors: Bakker W.T. , Joustra D.Sj.
Published: February 2019

The purpose of this paper is 1. Publishing some available coastal measurements and computations of more than local importance 2 Investigation on the influence of groynes in practice. 3. Investigation on the motion of the gullies in the outer deltas. The following conclusions are drawn 1. The gross littoral drift along the dutch coast is in the order of 1.5 to 2 mln m^/year, (computed with the CERC-formula) the resulting net drift is mostly within the order of accuracy of the computation. 2. The erosion of the areas with groynes was much less than the erosion of the adjacent areas, partially this effect is due to lee-side scour but mainly to decreased erosion in the protected area. 3. The gullies in the outer deltas of the Wadden mainly turned clockwise, which is probably the direction of the resultant transport there.
EFFECTS OF NONUNIFORM WAVE ENERGY IN THE LITTORAL ZONE
Authors: Goldsmith Victor , Colonell Joseph M.
Published: February 2019

Bi-weekly monitoring of four closely-spaced permanent beach profile stations located on the northeast end of Monomoy Island (Cape Cod) has revealed major variations in the amount of erosion and accretion occurring along this portion of the Massachusetts shoreline During the 27-month monitoring period a close relationship was observed between changes in the beach and offshore portions of the profiles Three distinct types of bars were noted (1) Subtidal bars which are parallel to the shoreline and located one to two thousand feet off those portions of the shoreline undergoing relatively small amounts of beach erosion, (2) Subtidal bars which are perpendicular to the shoreline and attached to areas of the shore undergoing large amounts of erosion, and (3) Large intertidal bars which are oriented obliquely to the shoreline and associated with the formation of the ebb-tidal delta and the resulting wave refraction patterns The large variations in erosion and accretion occurring along the beach at any one time are related to the nonumform distribution of energy within the waves arriving at this section of the coastline This nonunifortuity of wave energy is attributed to refraction of the waves around the irregular bathymetry offshore from Monomoy, and it appears to produce shoreline protuberances of sand which are flanked updrift and downdrift by erosional zones.
LITTORAL TRANSPORT AND ENERGY RELATIONSHIPS
Authors: Bajorunas L.
Published: February 2019

The littoral transport rates in the Great Lakes were obtained two distinctly different ways, long-term averages from drift accumulations and hourly averages were measured vn the St Clair River which reaevoes sand from Lake Huron beaches Statistical analysis of both the recorded energy elements and measured sediment transport rates indicates that a combination of energy elements and environmental factors consisting of wave power and duration, current speed, and length of shoreline produces the best correlation with the transport rate Dimensional analysis expands the process-response model by including sediment-size and specific-weight parameters.
SYNOPTIC OBSERVATIONS OF SAND MOVEMENT
Authors: Duane David B.
Published: February 2019

The U S Army Corps of Engineers' Coastal Engineering Research Center, in cooperation with the Atomic Energy Commission, initiated a multi-agency program to create a viable radioisotopic sand tracing (RIST) program Other agency participants in this program have been the Los Angeles District, Corps of Engineers, U S Air Force (First Strategic Aerospace Division), U S Navy (Pacific Missile Range), U S Army Mobility Equipment Command, National Aeronautics and Space Administration, and the State of California (Dept of Navigation and Ocean Development) CERC, together with the AEC's Oak Ridge National Laboratory has developed tagging procedures, hardware development, field surveys and data handling techniques that permit collection and analysis of over 12,000 bits of information per hour over a survey track of approximately 18,000 feet Data obtained with the RIST system can be considered as nearly synoptic observations of sediment transport m a single environmental zone or in adjacent beach, surf and offshore zones Using sand tagged with isotopes of gold, experiments have been carried out at several sites on the California coast Surf, Point Conception area, Point Mugu, and Oceanside Data from the studies carried out in beach areas unmodified by littoral barriers indicate that under a given set of wave conditions the alongshore velocity of sediment transport differs from zone to zone such that transport seaward of peakmg-breaking waves < transport on the beach face < transport in the plunge and surf zone Because of these differences, tracing surveys confined solely to the foreshore or offshore zones produce data only partially indicative of transport in the zone of immediate concern to coastal engineers.
SPECTRAL. COMPUTATIONS ON PRESSURE WAVE GAUGE RECORDS
Authors: De Carvalho Manuel Mandes , Ramos Fernando Silveira , Moraes Carlos de Campos
Published: February 2019

With a view to establish sea wave data processing procedures to be applied to records obtained at the Portuguese coast, a detailed study is made of different choices of certain parameters used in one-dimensional spectral analysis of a pressure wave gauge record Statistics computed by the selected spectral procedure are then compared with results of a Tucker-Draper analysis of the same record Finally a hindcast of sea conditions for the date and place of the record is made by different methods and comparisons with previous results are presented.
A Class of Probability Models for Littoral Drift
Authors: James William R.
Published: February 2019

The major goal in the development of sediment tracer technology is to produce an accurate method for the field measurement of short term volume littoral rate Many of the technical difficulties involved in tagging, injecting, and sensing the movement of radioisotope sand tracers in the littoral zone have been overcome by the RIST project However, quantitative determination of volume drift rate requires more than knowledge of tracer position in time and space A mathematical model is required to relate the flux of tracer material to the sediment flux A linear (or average) rate of tracer transport along the coastline can be measured to a fair degree of accuracy with tracers These measurements, when determined from tracers injected along a line source which span the transport zone, can be used to provide an estimate of an areal transport rate However, it is not obvious how to measure the third dimension, depth of transport This, of course, is needed to provide the desired estimate of volume transport rate This problem arises, even if the relation of tracer concentration to burial depth is everywhere known without error Sediment transport does not occur as a sheet of constant thickness moving at a constant rate If this were so tracer concentration would rapidly attain a uniform concentration over a fixed depth and no tracers would appear below that depth In fact no observations of the relation between tracer concentration and burial depth support this model as even a first approximation Studies such as those of Courtois and Monaco (1969) and Hubble and Sayre (1964) suggest that the concentration of tracers is related to burial depth in a complex fashion The concentration on the surface is finite, but not maximal The concentration increases with depth to some point where a maximum is reached and diminishes in a "long tailed" fashion.
SOME SAND TRANSPORT PHENOMENA OH COASTS WITH BARS
Authors: Dyhr-Nielson M. , Sorensen Torben
Published: February 2019

Longshore wave currents and their influence on the sand transport phenomena m the shore zone have attracted the attention of numerous researchers. Also the existence of transverse, secondary currents, superposing the longshore component, has been known for years, but less attention has been given to analysis of their effect on the sediment movement. This paper presents some examples of the influence, these relatively weak transverse currents may have on the processes in the shore zone. They have a parallel in the effect of secondary currents in alluvial streams, which, although weak, give use to such an impressive phenomenon as meandering. All conclusions below are based on simple, qualitative considerations of the physics of the system. A strict mathematical, quantitative approach to the problem does not seem possible with the present knowledge of the fluid dynamics in the shore zone, and much further research into these complex phenomena remains, of course, necessary.
CRATER-SINK SAND TRANSFER SYSTEM
Authors: Inman Douglas L. , Harris Roland W.
Published: February 2019

A sand transfer system that requires no surface impounding area and that can be installed and operated at low cost is proposed The system consists of a hydraulic jet assembly operating from the bottom of a sand crater A jet pump and suction mouth are located at the lowest point of a crater-like depression dredged into the sea floor The crater acts as a gravity-fed sink for sand and other cohesion I ess material, thus serving the dual purpose of a mechanism for collecting sand and a sub-surface impounding area for the accumulation of sand.
AN OFFSHORE BEACH NOURISHMENT SCHEME
Authors: Dalrymple Robert A.
Published: February 2019

The University of Florida has conducted a series of tests to evaluate the effectiveness of beach nourishment from offshore sources by a specially designed drag scraper The field work, over a nine-month study period, included hydrographic surveys, fluorescent sand tracing, and a sand sampling program for two scraper sites at Jupiter Island, Florida The conclusions provide information as to the effect of the borrow pits and the dredged sand on the beach characteristics, the mechanisms of the filling of the pits, and the efficiency of the drag scraper.
LABORATORY TESTS ON ARTIFICIAL SEAWEED
Authors: Price W.A. , Tomlinson K.W. , Willis D.H.
Published: February 2019

Tests are described m which the effect of artificial seaweed on bed sediment movements due to waves was studied in a model Water velocities near the bed and coal particle velocities on the bed, within the seaweed array, were measured over a range of wave conditions and densities of packing of the seaweed The water velocity measurements were erratic, probably due to additional turbulence caused by the seaweed Coal particle movements on the bed were slowed down in the presence of seaweed.
EXPERIMENTAL STUDY OF THE HYDRAULIC BEHAVIOUR OF INCLINED GROYNE SYSTEMS
Authors: Barcelo Julio Patriarca
Published: February 2019

This paper presents the results of an experimental study on the behaviour of inclined groynes and a short discussion on the optimization of groyne systems It supplements a paper presented at the XI Coastal Engineering Conference (London, 1968) In the present paper both studies are applied to the design of a groyne system looated to the south of the Tagus estuary (near Lisbon)j where a serious erosion has been under way.
CHARACTERISTICS OF SHINGLE BEACHES THE SOLUTION TO SOME PRACTICAL PROBLEMS
Authors: Wood A.M. Muir
Published: February 2019

Shingle beaches differ from sand beaches mainly in the mode of transport of the material and in the permeability of the beach. The typical beach forms are in consequence different and the typical problems of beach stabilisation require different types of solution* The mechanism of littoral drift of shingle is controlled predominantly by the action of the breaking wave, on a groyned beach a simple theory is advanced to relate drift to groyne length and spacing. Longitudinal sorting of shingle sizes is a specially notable sign of a stable beach* Well marked size-sorting transverse to the coastline is a more general characteristic. Examples of schemes of management are provided for a beach with high littoral drift and a beach which has to te controlled as artificial cells The accreting shingle beach may in suitable circumstances develop a steep in-shore profile - examples are given of such.
ESTUARY INLET CHANNEL STABILIZATION STUDY USING A HYDRAULIC MODEL
Authors: Lee Theodore T.
Published: February 2019

A hydraulic model study was conducted to determine the most feasible means of reducing shoaling into a coastal inlet channel that had been used by loaded Landing Ship Tank (LST) class vessels serving the port of Tan My near Hue, Republic of Vietnam The ultimate objective was to increase the time during which the channel will be open to navigation by improvements in physical configuration An extensive field data acquisition and analysis program was executed to provide basic information for model prototype correlation This incidentally resulted in the re-evaluation of several empirical formulae being used for prediction of littoral transport and of tidal currents The comprehensive field measurements of shoaling in the channel area also permitted the determination of the scale effects on the quantitative results of sediment deposition in the channel and on the time scale of bottom evolution The experiments were conducted systematically in three phases The three-dimensional studies for Phase I and II were conducted using a rigid bed, sand or walnut shell covered (1/250 horizontal and 1/50 vertical scale) hydraulic model of a 15 sq mi ocean-estuary land area Periodic long-crested waves tides tide/river induced currents were simulated in the model Phase I covered qualitative evaluation of nine improvement plans, from which a BEST PLAN," an upshore jetty to protect the existing channel, was selected Phase II covered qualitative and quantitative evaluation of four variants of the "BEST PLAN,' from which the most effective and economical variant was determined To insure reliability of quantitative results, comprehensive experiments were conducted using three different sediments (D50 = 0 41 mm and 0 90 mm, 7 = 1 35 for two types of ground walnut shells and D50 = 0 22 mm, 7 = 2 65 for sands), and three model scaling criteria (Froude Scaling, "Ideal Velocity" Scaling, and Modified Froude/Ideal Velocity Scaling) Phase HI covered two-dimensional model tests, in a 180 foot flume, of the stability characteristics of the proposed rubble mound type jetty on a movable bed The major conclusions of this study include (1) the jetty, as postulated in the BEST PLAN,' would reduce annual maintenance dredging requirements by 74 to 84 percent, (2) a systematic three phase model study such as used in this investigation is most feasible (from a time-consumption viewpoint, use of light weight materials such as ground walnut shells may be more economical than use of natural sands as model material), and (3) use of theory alone in predicting a tune scale for bottom evolution should be approached with caution especially where field data are not readily available.
TIDAL INLET PROBLEMS ALONG THE NEW ENGLAND COAST
Authors: Arpin Oscar E.
Published: February 2019

The New England Division of the United States Army Corps of Engineers has created and improved many harbors along the New England coast for the benefit of commercial fishing and recreational boating fleets A harbor, to be effective, must provide a protected area for boats and it must have a safe access, that is, a protected and stabilized tidal inlet A coastal inlet has been defined as a waterway connecting a bay, lagoon or similar body of water with a larger body of water The major engineering problems encountered in the development of harbors have involved stabilization of these inlets The problems have been caused by excessive littoral drift resulting from erosion of the shorefront adjacent to the inlets by wave attack Planning, designing, constructing, and modifying these inlets under very dynamic conditions is complex and difficult Each inlet is unique This paper discusses very briefly some of the problems encountered.
OFFSET COASTAL INLETS
Authors: Hayes Miles O. , Goldsmith Victor , Hobbs Carl H.
Published: February 2019

Offset coastal inlets are common on the coasts of New England and the northern Gulf of Alaska In both areas, the dominant waves approach the shore at an oblique angle, resulting in a strong net littoral drift The most common type of offset on these coasts is a downdnft offset (l e , the downdnft side of the inlet protrudes further seaward than the updnft side) Wave refraction around the ebb-tidal deltas at the inlets is an important process in the formation of the downdnft offsets, inasmuch as it creates a local reversal in drift direction just downdnft of the inlet, and allows sediment to accumulate there Associated with the offset appears to be a segregation of tidal current flow in the inlets, with the ebb flow being more channelized than the flood The type of inlet offset at any one location can vary through time Studies of the changes at the Hampton Harbor, New Hampshire, inlet from 1776 to the present show two reversals from updnft to downdnft offsets during that interval.
SCOUR AROUND A CIRCULAR CYLINDER DUE TO WAVE MOTION
Authors: Wells Donald R. , Sorenson Robert M.
Published: February 2019

A vertical circular cylinder to simulate a pile was installed in the Texas A&M Hydrodynamics Lab two dimensional wave tank along with a built up section containing a horizontal bed of fine sand This was subjected to monochromatic waves of differing characteristics and conditions for mcipi ent motion were observed for each of three sands Also, the magnitude and pattern of ultimate scour and the time interval required to reach this state were measured for six different conditions of wave steepness and relative depth These results were related to influential parameters, including wave, pile and sediment character istics, and developed by dimensional analysis with consideration of the literature pertaining to past work on the movement of sediment by oscillatory flow Conclusions regarding the critical flow velocity for incipient motion, the effect of the above parameters on incipient motion and ultimate scour depth, the time required tor maximum scour, the significance of eddies generated by the pile, and the catalytic action of the pile in causing the initiation of scour are presented The above conclusions are also generally discussed in light of the difficulties involved in extend ing the results to prototype conditions.
DIRECTIONAL SPECTRA FROM WAVE-GAGE ARRAYS
Authors: Panicker N.N. , Borgman L.E.
Published: February 2019

The ocean surface may be considered to be composed of many waves traveling at different directions with different frequencies A graphical plot showing the allocation of wave energy to the different component frequencies and directions is the directional spectrum Directional spectrum has many applications in Coastal Engineering Herein an analytical procedure is developed to obtain the directional spectrum from records of an array of wave gages The two methods developed are the "locked phase method" and the "random phase method The locked phase method can be used to obtain the distribution of both phase as well as energy of the waves with respect to frequency and direction and is a deterministic approach The random phase analysis, on the other hand, is more suitable for wind waves in the ocean and yields just the distribution of energy alone as in most other procedures of spectrum analysis The procedures programmed for computers are checked using simulated data and laboratory data Wave records of the Pacific Ocean obtained off Point Mugu, California, on a 5-gage array were analyzed using the method developed and examples of the directional spectra obtained are presented.
COMPARISON OF MODEL AND BEACH SCOUR PATTERNS
Authors: Herbich John B.
Published: February 2019

Artificial or natural barriers may be divided into two classes, those from which waves are reflected and those on which waves break In general, any intermediate type that gives a combination of reflection and breaking may set up severe erosive action of the beach m front of barriers When the reflected waves are superimposed on the incident waves a stationary spatial envelope of the combined incident and reflected waves is produced Previous laboratory studies indicated that the crests of the sand bed appear fairly closely under the nodes of the envelope and troughs of the scoured sand bed under the loops of the envelope The predominant scouring pattern had a spacing between crests equal to one-half the wave length Other studies by Keulegan and Shepard established characteristic parameters for bar and trough depth for laboratory conditions and for several field locations Their studies were compared with beach profiles taken along the Texas Gulf Coast.
STOCHASTIC ANALYSIS OF BEACH PROFILE DATA
Authors: Sonu Choule , Young Myron H.
Published: February 2019

Stochastic prediction of beach changes by means of a linear leastsquares transfer function requires a knowledge of power spectra Since most field data are too short to ensure stable analysis, an attempt was made to generate data artifically by a Monte Carlo simulation A beach profile transition model which considers the beach profile as a dynamic system allows beach width, sediment storage, and surface configuration to be determined m successive profiles and simulates beach cycles associated with random waves which are in sufficient agreement with the actual observation The simulated data are amenable to standard stochastic analysis to yield power spectra, cross spectra, coherence functions , and phase lags Comparison of the results with those derived from actual data shows reasonable agreement It appears that the process of beach sediment storage involves a combination of classes of Markov Gaussian random processes, whereas that of beach width resembles a white noise Coupling between these two parameters occurs in the lower frequency range with periodicities longer than about 8 days Moreover, the beach width shows phase advance before sediment storage Although the beach profile transition model requires further refinement, especially m regard to quantitative response to waves of various magnitudes and characteristics, the basic concept of the model is sound and will probably explain beach changes in various types of world coasts.