bluuebunny/crossref_metadata_2025 huggingface dataset:
DISPERSIVE TRANSPORT IN RIVER AND TIDAL FLOWS
Authors: Taylor R.B.
Published: June 2019

Analytical results are presented which describe the mechanisms of longitudinal dispersive mass transport in rectangular channels of finite and infinite widths for both unidirectional (river) and oscillatory (tidal) flow regimes. Emphasis is placed upon the discussion of results and the characteristics of longitudinal dispersive mass transport revealed by the analytical treatment. Expressions presented for the dispersion coefficient were obtained from solutions to four sets of boundary value problems for the velocity and concentration variation components u" and c". Examination of these expressions reveals that in oscillatory flow the dispersive mass transport is described by a type of resonant interaction between the period of oscillation and the time scales of vertical and lateral mixing. The analysis also shows that for oscillatory flow regimes the effect of lateral shear becomes negligible for very wide channels and the three dimensional solution collapses to the two dimensional case in which vertical shear and mixing effects dominate. It is shown analytically that this is not the case in unidirectional flows. For this case the lateral shear and mixing effects dominate the corresponding vertical effects and dispersive mass transport increases without bound with increasing channel widths.
TIDAL STREAM FLOW SOLVED BY GALERKIN TECHNIQUE
Authors: Smith L.H. , Cheng R.T.
Published: June 2019

The total discharges in a tidally influenced stream reach are known to be related to the stages (water levels) at the ends of the reach. The discharge-stage relationships can be derived from the conservation principles of mass and momentum under a few simplifying assumptions. Solutions of the governing equations with appropriate boundary and initial conditions give spatial and temporal variations of the flow in the reach. Practically, the most needed information are the instantaneous discharges, which, in many instances, provide guidance for water resources management decision making. Unfortunately, measuring the instantaneous discharge in a tidal reach is often difficult, tedious and costly. However, measuring the stages of a tidal reach is relatively simple, inexpensive and is done routinely. To determine discharges from measured water levels has been the subject of the present study.
CALIBRATION OF BRANCHED ESTUARY MODELS
Authors: Bennett James P.
Published: June 2019

Unsteady flow models of one-dimensional channels or of channel networks are commonly calibrated using a combination of stage (water surface elevation) and discharge observations. In tidally influenced areas these observations may extend in time over several tidal cycles. Where there is an important mean flow discharge such as in a river harbor, observations must be repeated for a number of representative mean flow conditions. Stage observations are commonly collected using recorders coupled to water surface floats mounted at various points on the channel banks. The initial costs of purchasing the recorders, installing them, and in the leveling necessary to determine datum are the primary expenses involved in collecting stage observations. For these observations the cost per observation decreases as the number increases. In tidally influenced channels, accurate one-dimensional instantaneous discharge measurements are difficult if not impossible to obtain because of the rapidly changing flow velocity. In many locations, discharge measurements cannot be made throughout a tidal cycle because of safety restrictions. Finally, with respect to stage information, the cost of collecting discharge information can be extremely high. In addition, the cost per observation does not decrease with the number of observations. With respect to the boundary conditions used to drive them, there are two main classes of unsteady flow models, the stage-stage models and the discharge-stage models. The former are driven by inputs of stage at all important external boundary points. The primary purpose of the stage-stage model is to determine the time history, or an average value of downstream discharge. Discharge-stage models are driven upstream by steady or time variable observed or hypothetical discharges and downstream by observed or hypothetical stages. This type of model is used primarily in conjunction with solute transport models in predicting the location and concentration of dissolved substances, as in dissolved oxygen modeling.
MOVABLE BED TIDAL INLET MODELS
Authors: Jain Subhash C. , Kennedy John F.
Published: June 2019

Stabilization of tidal inlets is a major engineering problem that is frequently encountered in the development of harbors. The planning, design, and modification of these inlets under the dynamic conditions that generally characterize their surroundings is, at best, a complex and uncertain undertaking. Prediction of the sedimentary response of an existing inlet to artificial improvements and to changing environmental conditions, or of a new inlet to the expected ambient conditions, and the optimization of the layout in order to minimize undesirable accretion or erosion are major elements in the design of tidal inlets. Because of the complexity of the problem, movable bed hydraulic models often are employed, despite the questions that surround their validity, to investigate these responses and to guide designs. The success of a movable bed hydraulic model depends upon the proper choice of similitude conditions and modeling criteria. Unfortunately, the conditions of similitude still are not well defined, as many of the phenomena constituent to the processes involved are yet to be elucidated adequately and formulated. Moreover, it is not possible to satisfy simultaneously all of the similitude conditions that arise. The required grain size and density of the model bed material, the current exaggeration that may be required, the effects of geometric distortion, etc. cannot be determined by straightforward computations. These must be chosen to obtain the most favorable balance between all relevant phenomena. The criteria of similitude generally are specified by experimenters who have previous experience with this type of model. The execution of a model studies of this type is, therefore, largely an "art" and entails major elements of subjectivity. The Iowa Institute of Hydraulic Research, under contract to Coastal Engineering Research Center, U.S. Army Corps of Engineers, is presently (1976) conducting a study to evaluate the reliability and effectiveness of movable bed, tidal inlet, hydraulic models as predictors of prototype behavior. The main emphasis of this study is on comparison of model predictions with observations made in the prototypes, and evaluation of model performance in the light of: (i) the criteria of similitude adopted; (ii) the sedimentary material and instrumentation utilized in the models; (iii) the experimental procedure followed; (iv) the quality of the prototype data utilized in verification of the models; and (v) the degree and accuracy of model verification. The scope of this study is limited to those models in which the area of interest is composed entirely of movable material and not of just a thin erodible layer placed over a fixed bathymetry.
PLANFORM INFLUENCE ON FLUSHING AND CIRCULATION IN SMALL HARBORS
Authors: Nece Ronald E. , Falconer Roger A. , Tsutsumi Toshiro
Published: June 2019

Laboratory data showing the influence of planform geometry on the tidal flushing characteristics of small harbors of simple surface shape. The tide ranges, water depths, and planform areas are typical of those encountered in small-boat marinas in Puget Sound, Washington. Each harbor investigated had a single, asymmetric entrance. Flushing and circulation patterns within such harbors depend strongly upon the characteristics of the angular momentum established within the basin and upon the effective penetration distance into the basin of the stream of ambient water entering the harbor on the flood tide. Experimental results confirm that best gross tidal flushing occurs when rectangular harbors have an aspect ratio L/B near unity, and that rounding interior corners of the basin has little effect on the gross tidal flushing but does improve local exchange. Aspect ratios L/B less than 3 lead to the creation of more than one circulation cell (gyre) within the basin.
ENVIRONMENTAL IMPACTS ON AN ISLAND COMMUNITY
Authors: Chapman Gordon A.
Published: June 2019

The environmental impacts of coastal engineering projects generally affect island communities to a greater degree than they would affect continental land mass communities. This occurs because of the smaller land area; close interdependence and interaction of land and sea communities, both natural and human; and relatively small projects having relatively large overall impacts on island ecosystems. The natural flora and fauna of Pacific Islands have developed rather precariously unbalanced communities that are extremely fragile and susceptible to change, both natural and man induced. This susceptibility dictates that, where possible, man induced or proposed changes, such as coastal engineering projects, should be designed such that as little change as possible occurs to the natural environment. Additionally, the natural resources of island communities are generally limited and this too dictates that conservation practices be employed that assure the highest and best use of those limited resources. The purpose of this paper is to indicate the environmental effects of a major coastal engineering project on an island community. This will be accomplished by describing the environmental quality control monitoring program that has been performed as an integral part of the Honolulu International Airport (HIA) Reef Runway construction project on Oahu, Hawaii, and presenting the initial findings of that environmental monitoring program. The Honolulu International Airport reef runway planning and design began in earnest in 1968 and 1969 with hydrographic and topographic surveys, foundation investigations, two- and three-dimensional hydraulic model studies, and environmental studies that were conducted (J. K. K. Look, 1970; Berger, 1971; Sunn, et_ al_, 1969). These studies, and others, were utilized to determine the technical feasibility, and to gather the engineering and environmental data for final design and construction. The Reef Runway, located south of the HIA runway system on the fringing coral reef, seaward of Keehi Lagoon, in Mamala Bay, is 12,000 feet long and 200 feet wide. The runway and taxiway complex is protected from the sea by a 16,000-foot long protective structure constructed of rock and dollose (Figure 1).
WAVE INDUCED OSCILLATIONS OF HARBORS WITH VARIABLE DEPTH
Authors: Raichlen F. , Naheer E.
Published: June 2019

A numerical method is presented to treat the wave-induced oscillations of a harbor with a variable depth and width. A two-dimensional finite difference approach is used inside the harbor matched at the entrance to a solution for the open-sea based on the Helmholtz Equation which includes incident, reflected, and radiated wave energy. Examples of the response and the modal shapes of the water surface are presented for harbors with simple and complex shapes.
APPLICATION OF CERC SPECIAL REPORT NO. 2
Authors: Dunham James W.
Published: June 2019

The purpose of this paper is to discuss the new manual titled Small Craft Harbors: Design, Construction and Operation, published by the D. S. Army Corps of Engineers Coastal Engineering Research Center (CERC) as Special Report No. 2 dated December 1974. The objective of the manual is to enable anyone with a basic engineering background to plan and design small craft harbors or do so with the help of one or more specialists. The manual outlines methods of investigating the problems involved and the various engineering, economic and environmental criteria to be applied. It covers much of the planning and design considerations discussed by the A.S.C.E. Committee on Small Craft Harbors in manuals and reports on engineering practice, #50, "Report on Small Craft Harbors 1969". However, it also incorporates a considerable amount of additional information in the form of special design and construction techniques, certain rules of thumb commonly accepted in marina design practice, and observations as to elements of good practice in this field. It provides a compendium of planning data gleaned through a nationwide canvassing of marina operators, marina design engineers, and trades people who provide commonly used marina construction products. Also included in the manual are some of the design and construction requirements of various Federal, state and local government agencies having jurisdiction over, or assisting with the development of small craft harbors.
INTERACTION OF WAVES AND A TURBULENT CURRENT
Authors: Van Hoften J.D.A. , Karaki S.
Published: June 2019

An experimental investigation was made to study wave-current interaction. Wave amplitude attenuation was measured along a laboratory wave channel to compare wave dissipation with and without flow. Mean, wave, and turbulent velocities were also measured to determine the modifications of the flow imposed by the gravity waves propogating with the current. The process of energy transfer in the wave current system was studied. Energy was found to be extracted from the waves, diffused downward and dissipated by an increase in bottom shear stress.
TRANSFORMATION OF NONLINEAR LONG WAVES
Authors: Shuto Nobuo
Published: June 2019

Kakutani's equation is extended to include the effects of variable width of the channel and the bottom friction. Based on the equation, several solutions are derived and compared with experimental results. For example, Green's law is obtained if the nonlinearity, dispersion and bottom friction are neglected. With the nonlinearity included, it is shown that the wave amplitude follows Green's law and at the same time the wave profile deforms due to the nonlinear effect. Discussion of the present paper is mainly focused on the effect of the bottom friction. From the experimental results of cnoidal waves in a channel of constant depth and width, on the bottom of which artificial roughnesses are planted, it is shown that the friction coefficient estimated from Kajiura's theories gives good agreements, thus confirming the validity of the method of conversion, proposed in the present paper, between sinusoidal and cnoidal wave motions. Change in height of cnoidal waves on a slope is also solved. The friction coefficient determined from wave characteristics and bottom conditions, by means of Kajiura's theories and the method of conversion stated above, is used in the comparison with experimental results. Theoretical prediction agrees very well with experimental results.
RECENT DEVELOPMENTS IN THE STUDY OP BREAKING WAVES
Authors: Longuet-Higgins Michael S.
Published: June 2019

The sight and sound of breaking waves and surf is so familiar and enjoyable that we tend to forget how little we really understand about them. Why is it, that compared to other branches of wave studies our knowledge of breaking waves is so empirical and inexact? The reason must lie partly in the difficulty of finding a precise mathematical description of a fluid flow that is in general nonlinear and time-dependent. The fluid accelerations can no longer be assumed t o be small compared t o gravity, as in Stokes's theory for periodic waves and the theory of cnoidal waves in shallow water, nor is the particle velocity any longer small compared to the phase velocity. The aim of this paper is to bring together s ome recent contributions to the calculation both of steep symmetric waves and of time-dependent surface waves. These have a bearing on the behaviour of whitecaps in deep water and of surf in the breaker zone . Since spilling breakers in gently shoaling water closely resemble solitary waves, we begin with the description of solitary waves of limiting amplitude, then discuss steep waves of arbitrary height. The observed intermittency of whitecaps is discussed in terms of the energy maximum, as a function of wave steepness, In Sections 6 and 7 a simpler description of steady symmetric waves is proposed, using an asymptotic expression for the flow near the wave crest. Finally we describe a new numerical technique (MEL, or mixed Eulerian-Lagrangian) with which it has been found possible to follow the development of periodic waves past the point when overturning takes place.
WAVE SHOALING OF FINITE AMPLITUDE WAVES
Authors: Yamaguchi Masataka , Tsuchiya Yoshito
Published: June 2019

Wave shoaling is calculated, based on finite amplitude wave theories on a uniform depth which were extended by the authors using the Stokes second definition for wave celerity. Change of wave characteristics with decrease in water depth is discussed from numerical computation, and difference in shoaling characteristics is considered in comparison with results obtained from usual wave theories by the first definition. Theoretical results are compared with preliminary experimental ones on the wave transformation in shoaling water conducted by the experimental facilities satisfying the physical conditions corresponding to the definition for wave celerity as well as possible, and the validity of each theory for practical purposes is investigated.
REFRACTION OF FINITE-HEIGHT AND BREAKING WAVES
Authors: Walker James R.
Published: June 2019

The primary objective of this study was to ascertain the influence of wave height and breaking on wave refraction over a three-dimensional shoal. The subject wave transformations were studied in an hydraulic model. Wave shoaling, decay in the breaker zone, and phase velocities were analyzed in a base test series over a bottom slope of 1:30. A second test series was conducted over a three-dimensional shoal. Wave patterns were photographed and wave heights and celerities were measured. The measurements were compared with wave refraction patterns and coefficients computed by analytical methods. Wave shoaling observed over the constant 1:30 slope was 25 percent greater than predicted by Airy theory at the breaking point for wave steepness H0/L0=.030 and 50 percent greater than predicted for H0/Lo = -002. Shoaling measurements were compared with other empirical data sets, confirming the inadequacy of commonly used practice using linear wave theory near the breaker zone. The celerity measurements indicated that the non-breaking celerity was given by C = (1+.25 H/d)Ca, where Ca is the Airy celerity. The discussion and results give a basic understanding of wave refraction near the breaker zone, supplementing analytical papers on refraction procedures using finite amplitude wave theories.
THREE-DIMENSIONAL CONDITIONS OF SURF
Authors: Wood William L.
Published: June 2019

Wave height variability along the crest of breaking waves is shown to be a significant factor in the assessment of surf zone dynamics. Variations in excess of 50 percent of the maximum wave height can occur along a single crest without significant variations in bathymetry. The horizontal scale of this longshore variability in crest height corresponds to the wave length of incident breaking waves. Four possible mechanisms for this variability are postulated and then evaluated individually on the basis of field observations. A major result of these evaluations is that two-dimensional shallow-water wave equations appear to be inappropriate for expressing natural surf zone wave transformations and water motions even under the condition of waves encroaching on a plane sloping bottom. Consequently, three-dimensional equations of surf should be used for describing most natural surf zone dynamics.
ENERGY SPECTRA OF IRREGULAR SURF WAVES
Authors: Busching Fritz
Published: June 2019

The investigations under consideration are based on synchronous measurements of water level deflections n(t) at some positions in a beach profile with a slope of approximately 1:40. Surf conditions are studied during a severe storm surge as well as during periods of attenuating wave action. By the use of a FOURIER ANALYZER 40 energy spectra are calculated which are also presented in integrated form (co-cumulative spectra). Because of different site arrangements it is possible to analyze the deformation of the spectra due to tide dependent changes of the water depth as well as due to coastward decreasing water depth. It happens that there are some phenomena associated with certain frequency bands. With the water depth decreasing the energy densities in surf spectra are distributed over a wider frequency band. In the present case unbroken waves are characterized by energy spectra in which at least 90 % of the energy is represented by FOURIER components in the frequency range 0 - f - 0.5 Hz. Increasing distribution of the energy densities over a wider frequency band represents at first breaking and finally broken waves. Sometimes the amount of energy coastward of the surf zone is higher than seaward of the breakers. This phenomenon can be explained by refraction effects caused by local nearshore bathymetry. All of there investigations were sponsored by the DEUTSCHE FORSCHUNGSGEMEINSCHAFT (German Research Foundation).
WAVE SPECTRUM OF BREAKING WAVE
Authors: Sawaragi Toru , Iwata Koichiro
Published: June 2019

By wave breaking, an incident monocromatic wave is transformed to a wave composed of its harmonic frequency waves inside a surf zone. Based on a dimensional consideration, the "-1 power law ", the "-2 power law ", the "-2/3 power law " and the "-1/2 power law " on the wave height spectrum ,H(f), are derived as sorts of equilibrium spectra. These spectra except"-l/2 power law" are shown to agree with experimental data.
CONSIDERATION ON FRICTION COEFFICIENT FOR SEA BOTTOM
Authors: Sawaragi Toru , Iwata Koichiro , Kubo Masayoshi
Published: June 2019

A bottom friction is an effective factor which will prove the deformation of progressive waves in shallow water, and many investigators have obtained the friction coefficients from field observations. However, they have not considered the effect of turbulent loss due to sand ripple at a sea bottom. The authors, first of all, study on the friction coefficient for artificial fixed ripple by using the boundary layer theory of rough turbulence, and a new formula on the friction coefficient is proposed. The proposed friction coefficients are compared with Zhukovets' experimental results which were performed on a movable bed, and it is found that the theoretical friction coefficients for artificial fixed ripple have to be modified in order to apply for the natural beach. Lastly, the wave deformation due to the bottom friction on the movable bed is calculated by the modified friction coefficient and the effect of bottom friction on the wave deformation is discussed.
NON-UNIFORM ALONGSHORE CURRENTS
Authors: Gourlay Michael R.
Published: June 2019

Alongshore gradients of breaker height have been shown to significantly influence the velocities and circulation patterns of nearshore current systems. Experimental data from an idealized laboratory experiment shows that the form of the nonuniform wave generated current system resulting from diffraction behind an offshore breakwater is essentially determined by the beach-breakwater geometry while its magnitude depends upon the wave height. Furthermore the current may produce significant increases in the magnitude of the wave set-up within the three dimensional system. For the case investigated, where the alongshore gradient of breaker height is comparatively large, the maximum mean alongshore current velocity is not greatly affected by bottom resistance and may be computed for plunging breakers from a relation of the following form.
DECOMPOSITION Of CO-EXISTING RANDOM WAVE ENERGY
Authors: Morden Dennis B. , Richey Eugene P. , Christensen Derald R.
Published: June 2019

Of the several transformations that water waves may undergo, the phenomenon of reflection has received relatively little quantitative attention, although the analyst is sensitized to reflection in a qualitative way. Commonly the investigator is interested in progressive or transmitted waves and the characteristics of reflected waves and the energy dissipated during the reflection process are of little consequence. There are, however, certain structures, such as piers, floating bridges, bulkheads, etc., where waves reflecting from the structure can be of concern if they should impinge on a site or shoreline sensitive to a new, or changed, wave climate. Quantitative assessment of the energy dissipated during reflection is essential to the evaluation of devices which are intended to reduce site interaction problems and/or reduce the loading on structures and anchor systems. This paper examines the analysis of sea states where wind-generated waves and their reflection co-exist. Using the results of a field test the characteristics of co-existing sea states are discussed. The decomposition of these waves to obtain separate incident and reflected wave spectra requires two applications of spectral analysis. First, spectral estimates are computed from co-existing wave data acquired simultaneously at multiple, fixed sensor locations. These spectra are then divided into frequency increments and the amplitude associated with each increment used as an independent input into a technique to decompose the co-existing waves into appropriate incident and reflected wave spectra. Because the incremental amplitudes of the original spectral estimates are used as independent inputs, the shape and accuracy of these original estimates naturally have a profound influence on the final separated wave spectra. Various spectral estimating techniques were used on the field data and the accuracy of the results were compared to three validation criteria. Because the findings and discussion are validated primarily by the analysis of specific data it seems appropriate to first describe the relevant features of the field test. Though the present study involves deep water waves and zero transmission, the principles apply equally well to any situation where wave reflections are of interest.
PHYSICS AND MATHEMATICS OF WAVES IN COASTAL ZONES
Authors: Lundgren H.
Published: June 2019

This paper presents a discussion of four methods available for the computation of small amplitude periodic waves in coastal zones of arbitrary topography. With no reflections (or reflection from a single structure) the methods that proceed in space (Refraction and Propagation) or time (TJLmestep) seem the natural ones from a physical point of view. With repeated reflections, recourse must he taken to the solution of an Elliptic "boundary value problem. - It is suggested that a P-method based on (energy) flux lines and energy fronts be developed for cases where the R-methods give crossing orthogonals.
HURRICANE TIDE FREQUENCIES ON THE ATLANTIC COAST
Authors: Ho Francis P.
Published: June 2019

Hurricane surge Is a serious and not uncommon event along the Gulf of Mexico and Atlantic coasts of the United States. The most disastrous display of hurricane forces in recent decades was by Camille, which struck the Mississippi coast in 1969. The storm tide reached 24.6 ft MSL,, Reported storm tides on the Atlantic coast have reached elevations of 15 to 20 ft in Florida, Georgia, the Carolinas and New England. One of the latest coordinated efforts to alleviate losses from hurricanes - supplementing warning services, community preparedness, and evacuation plans- is the Flood Insurance Program.
AUTOMATED FORECASTING OF EXTRATROPICAL STORM SURGES
Authors: Pore N. Arthur
Published: June 2019

The Atlantic coast of the United States is affected by extratropical storm surges several times each winter. The most devastating storm of this type on record is that of March 1962. This storm caused damage estimated at over $200 million. The National Weather Service has developed an automated technique for forecasting such storm surges. Statistical forecast equations have been derived for 11 locations from Portland, Me., to Charleston, S.C. Input data to these equations are values of sea-level pressure as forecast by an atmospheric prediction model of the National Meteorological Center. A sample forecast equation is shown. The method was put into operation in 1971. Forecasts are transmitted via teletypewriter and extend to 48 hours at 6-hour intervals. A sample teletype message is shown. Forecasts of the devastating storm surge of Feb. 19, 1972, are discussed. These forecasts agreed reasonably well with observations of the storm surge. Experience with the method indicates it to be useful and therefore it will be expanded to include additional forecast locations.
GENERALIZED MODEL FOR STORM SURGE
Authors: Yeh Gour-Tsuy , Yeh Fei-Fan
Published: June 2019

A two-dimensional numerical simulation model of storm surges based on the vertically integrated hydrodynamic equations of continuity and momentum is adopted. The model embodies the inundation over the lowlying land surface with moving water-land interfaces. Kind stress coefficient is considered not only function of wind speed but also dependent on the temperature differential between air and water. Bottom stress is treated by an evaluation of convolution integrals over the surface slope pressure depression and wind shear. The contribution of momentum by river inflows is taken into account. Particular attention is directed to the treatment of nonlinear terms in the governing equations to insure the improvement of numerical stability and accuracy. The model is applied to the New Jersey Coastal area and reproduces the historical storm surges quite well both at Atlanta City and Sandy Hcok.
SIMULATION MODEL FOR STORM SURGE PROBABILITIES
Authors: Fallah M.H. , Sharma J.N. , Yang C.Y.
Published: June 2019

Storm surge and its Impact on the coastal regions have been of interest to many researchers and engineers for a long time. Deterministic models based on classical hydrodynamics can be used for reliable predictions only for short terms, e.g. up to 24 hours for which the characteristics of the storm can be projected accurately. Long-term predictions, on the other hand, is a statistical problem due to the random nature of the storms. Such long-term prediction is becoming increasingly important as the coastal regions are rapidly developed into residential, recreational and industrial areas. One of the first statistical studies on coastal storm surge predictions was published in 1961 by Wemelsfelder who used a Poisson probability law to fit the observed high tide data at Hook of Holland. From this fitted law, risk curves for long-term in years can be constructed for design purposes. In 1970 Yang et al applied the extreme value model to fit storm surge data for Atlantic City, New Jersey and Breakwater Harbor, Delaware. This so-called "purely" statistical method is sound in concept and simple to use. It has some serious limitations, however. First, it requires a collection of long term data (say 100 years for reliable design predictions) which is difficult to obtain in general. Secondly, the prediction for one location is not valid in general for other locations even when they are not far apart. To overcome the first limitation on the unavailability of long-term data at least partially, it is recognized that although storm tide data is limited, the general meteorological data is relatively abundant, so that more data on storm tide can be derived from meteorological data (wind field) via a hydrodynamic analysis. The analysis, of course, involves a general coastal area and consequently, the spatial variation of the storm tide can be predicted and the limitation on the location can be removed also. These observations lead to the concept of a combined statistical and hydrodynamic model which takes into account both the randomness of the long-term meteorological data and the physics of the storm surge.
TSUNAMI PROPAGATION IN THE PACIFIC OCEAN
Authors: Engel Manfred , Zahel Wilfried
Published: June 2019

The Alaska tsunami of March 28, 1964, caused by a tectonic uplift, propagated across the Pacific Ocean and was even recorded at the shores of New Zealand and the Antarctica. The large distance propagation of this tsunami is investigated by a numerical model based on the shallow water equations. The model includes bottom friction, eddy viscosity and Coriolis acceleration and yields the water elevation and the vertically integrated current velocity. The generation mechanism is given by a simplified initial condition, that is derived from the observed average uplift of 1.8 m for an area of 110000 km on the Continental Shelf. The computed tsunami propagation is presented by means of the first wave travel time and height on Pacific Ocean maps and by giving sea surface time series for selected stations. These computed results are compared with observations, especially considering the limitations of the model due to the coarse grid net having been used.
TRANSFORMATION OF TSUNAMIS IN A COASTAL ZONE
Authors: Nakamura Shigehisa , Higuchi Haruo , Tsuchiya Yoshito
Published: June 2019

In order to obtain fundamental information to establish warning practices and effective countermeasures against the tsunamis on the coast, the authors have studied on refraction of the tsunamis propagating into Osaka Bay and on tsunami spectra. ^he refraction of the tsunami is studied by a numerical computation for a program of refraction and shoaling of small amplitude wave. An example is shown for Chilean Tsunami in I960 to reveal that the refraction is an important factor to study on the tsunami wave height distribution along the coast of Kii Peninsula and Shikoku Island. The mareograms of the tsunamis are analyzed to obtain power spectra to study on transformation of the tsunamis from the Pacific ocean to the head of Osaka Bay. The result suggests that it is necessary to be careful to study on transformation of the tsunamis with use of the refraction diagram because the tsunami is not a simple monochromatic and small amplitude plane wave. A brief remark is given for the analysis of the tsunami as non-stationary process.
TSUNAMI INUNDATION PREDICTION
Authors: Bretschneider Charles L. , Wybro Pieter G.
Published: June 2019

This paper concerns the run-up and inundation characteristics of tsunami surges. The forces and moments produced by the waves are not discussed, however, the proposed technique does provide the necessary information for their determination. The method relies on the knowledge of the wave elevation at the coast (as determined from historical data or other means) and an estimation of the bed roughness. The considerations and calculations involved in determining these parameters are discussed in detail. Twenty-four observed run-ups on the island of Hawaii in the case of the 1946 Aleutian tsunami, and 18 run-ups on the island of Maui for the Chilean 1960 tsunami are used to illustrate the technique. Methods are also presented to predict the shoreline heights and extent of inundation of tsunami surges where historical data is not available.
NUMERICAL MODELS OF HUGE TSUNAMIS OFF THE SANRIKU COAST
Authors: Iwasaki Toshio
Published: June 2019

Although numerical computations of the generation and propagation of tsunamis are successfully achieved in recent years, modeling of their wave sources is still a big problem. Three kinds of, wave source model, that is statistical, oceanographic and fault model, are studied in this paper. It is found that the first model gives reasonable wave heights as shown in the previous paper, the second one presents roughly one half of those for the first model and the last one produces too small wave heights. Based on the analysis of computed results, nature of undulations off from the shore boundary, directivity of wave propagation and the spindle shaped leading part are discussed. Comparing magnitude of various wave parameters for the leading wave along the minor axis of the wave source, it is shown that the long wave approximation modified by the slope effect illustrates the tsunamis in deep region of the sea and the slope effect is most dominant in shallow region.
QUANTITATIVE DESCRIPTION OF SEDIMENT TRANSPORT BY WAVES
Authors: Madsen Ole Secher , Grant William D.
Published: June 2019

With the apparent desire of man to move some of his activities into the offshore region the problems associated with the assessment of the impact of large structures in this environment will be of increasing importance. One of the impacts of a large offshore structure, such as for example the Atlantic Generating Station proposed by Public Service Electric and Gas Company of New Jersey, would be its effect on the wave and current pattern in the vicinity of the structure. These changes in wave and current conditions will induce changes in the sediment transport pattern and may disturb an existing equilibrium thus causing large changes in bottom topography in the vicinity of the structure. These topographical changes may extend all the way to the adjacent shoreline and thus cause deposition in some and erosion in other areas. To assess the severity and extent of topographical changes induced by an offshore structure an ability to quantify not only the effects of the structure on the wave and current pattern but also the mechanics of the interaction of the resulting fluid motion with the bottom sediment is clearly needed. The purpose of this paper is to establish quantitative relationships for the fluid-sediment interaction in this environment.
LONGSHORE TRANSPORT PREDICTION - SPM 1973 EQUATION
Authors: Galvin Cyril , Vitale Philip
Published: June 2019

The 1973 Shore Protection Manual (SPM) predicts longshore transport rates that are 83% higher than its 1966 predecessor, for the same wave conditions. This upward revision is the result of concurrent increases due to (1) deletion of all laboratory data used to establish the 1966 prediction, (2) addition of Komar's (1969) field observations, and (3) limiting energy flux values computed from previously unused data obtained at Santa Barbara (Johnson, 1952). A derivation based on conservation of energy shows that P. is the longshore component of the energy flux confined between two wave orthogonals spaced a unit distance apart in the longshore direction, and that a term previously identified as the onshore component of energy flux is identical with the total energy flux in the direction of wave travel between these orthogonals. Use of submerged weight transport rates has no engineering benefit at the present time because: (1) all available data are in terms of volume rates, (2) conversion to submerged weight requires estimates of the void ratio and sand grain density which have been assumed constant in practice, and (3) the engineering problem needs volume rates which would require reconversion back to volume rates if an immersed weight prediction were established.
APPLICATION OF A SEDIMENT TRANSPORT MODEL
Authors: Fleming C.A. , Hunt J.N.
Published: June 2019

A mathematical model for sediment transport under waves has been developed from concepts that have been used successfully for unidirectional flow. This model has been combined interactively with numerical models of wave refraction, wave diffraction, longshore currents and circulation currents in order to predict local topographical changes in the vicinity of a cooling water intake basin for a nuclear power station. The sediment model is calibrated using field data of sediment concentration profiles. Verification and adjustments may be made by analysing deep water wave statistics corresponding to periodic beach and hydrographic surveys. The model can be used to investigate the effects of any wave climate and consequently different layouts of coastal structures can be examined very rapidly. For the particular problem considered it was necessary to optimise the configuration of the breakwaters forming a cooling water intake basin in order to minimise the sediment concentration at the intake, estimate maintenance dredging quantities and investigate extreme events.
GREAT LAKES WAVE INFORMATION
Authors: Resio D.T. , Hiipakka L.W.
Published: June 2019

The lack of reliable Great Lakes wave information has long been a problem for the Corps of Engineers and others involved in planning and design along Great Lakes coasts. In recent years this need has been accentuated by increased water levels and increased demand for coastal land use. The Corps need for wave information became critical with the passage of the River and Harbor Act of 1970 (Public- Law 91-611) Section 123 of this legislation authorized design and construction of contained spoil disposal facilities having a ten-year capacity to hold polluted dredged material. The North Central Division of the Corps of Engineers (NCD) is responsible for dredging 117 navigation projects and connecting channels in the Great Lakes. Of these, 59 are considered polluted, necessitating construction of 41 diked disposal sites at an estimated cost of over $300,000,000. With a program of this magnitude, it was apparent that unnecessary conservatism in design had to be minimized through development of the best wave information base that the state-of-the-art could provide. A project was initiated at the Corps of Engineers Waterways Experiment Station (WES) under the sponsorship of NCD to supply design wave information. After a review of all possible sources of available wave information and the potential for obtaining additional gage data, it was determined that a wave hindcast program might best meet the immediate needs of NCD. The actual study has been divided into four phases: a. The estimation of over-lake winds, b. The establishment of a wave hindcast technique, c. The analysis of waves from model outputs, and d. The evaluation of errors in Phases a, b, and c.
CONCEPT FOR INFERRING THE LITTORAL DRIFT TREND
Authors: Hattori Masatoaro , Suzuki Takasuke
Published: June 2019

To infer the rate and prevailing direction of littoral transport along a given coast is of prime importance in the functional and rational designing of coastal structures as well as in the environmental consideration of coastal zones. Many efforts have been made to develop the inferring method from field evidences such as 1) coastal landforms and shore configurations in the vicinity of existing structures1'~°', 2) alongshore variations in beach and bed sediment properties V)~12)j 3) statistical analysis of incident wave properties 13)~16)/ 4) movements of natural or artificial tracers 17)-20)^ an(j so on_ Among these evidences, the alongshore variations of indigeneous beach materials have served as a powerfull, practical and economical tool in the inference of general trend of littoral transport. Properties of beach sediment, such as grain size of sand and volume and shape of gravels, indicate some progressive trends with alongshore distance from supply sources2D. Thus the littoral transport direction along a given coast is inferable from variations in beach sediment properties. However, inferring criteria of prevailing direction from variations in various beach sediment properties have not yet been fully established. For example, the prevailing direction of littoral transport should be defined to be alongshore component of intergrated vector of littoral transport during several years or decades along a given coast. But this direction is often confused with the alongshore dislocating or traveling direction of beach sediment, which is indicated by the variations. It has also been concluded simply that the variation series obtained from backshore samples show a long-term trend of littoral transport, whereas those from foreshore indicate a short-term trend such as seasonal changes. In this inferring procedure any considerations have never been paid on differences in grain size of beach materials (sand and gravels) and in wave conditions during the period of field study. Rate or intensity of littoral transport has scarcely been inferred from the variation series of beach sediment properties even quantitatively. To solve these problems, the present study proposed a new concept on the basis of field evidences obtained on the Enshu Coast, Central Japan.
EQUILIBRIUM PROFILES AND LONGSHORE TRANSPORT OF COARSE MATERIAL UNDER OBLIQUE WAVE ATTACK
Authors: Van Hijum E.
Published: June 2019

In order to obtain design criteria for artificial gravel beaches, a research programme was drawn up to study the behaviour of gravel beaches under wave attack. The present paper gives the main results of the investigations into beach formation and equilibrium profile characteristics, including the longshore transport rate of beach material under regular wave attack with varying angles of wave approach,
STABILITY AND IMPULSE RESPONSE OF EMPIRICAL EIGENFUNCTIONS
Authors: Winant Clinton D. , Aubrey David G.
Published: June 2019

The statistical method of empirical eigenfunctions has been applied to four years of beach profile data. The eigenfunctions associated with the three largest eigenvalues are shown to be stable for data sets of one, two, three, and four years length, and they correctly describe beach changes caused by storm activity. The usefulness of the eigenfunction representation is confirmed as a concise means of representing beach profile variability.
WAVES OFF TAICHUNG COAST OF TAIWAN
Authors: Chang Charles C.C. , Wang M.H. , Juang J.T.
Published: June 2019

Many coastal engineers have made studies on the characteristics of waves, but most of them concentrated on waves of the open ocean. Due to the environmental difference, the result drawn for open ocean waves may not be applied to straits or the continental shelf. Based on the observed data, the authors intend to obtain some characteristics or tendency of wave condition in the Taiwan strait. Correlationship among wave parameters and meteorological factors is also examined. Comparisons to the result for open ocean waves are made to supply information for planning, design and construction of coastal structures on the coast of the strait. These studies are also useful for wave prediction in the strait area.
THREE DIMENSIONAL TESTS ON DYNAMIC EQUILIBRIUM AND ARTIFICIAL NOURISHMENT
Authors: Kamphuis J.W. , Myers R.M.
Published: June 2019

A three dimensional facility for testing dynamic equilibrium and artificial nourishment of beaches was developed. Specific conclusions are drawn with respect to trap location and re-reflection of waves. It was found that dynamic equilibrium is achieved faster in three dimensional tests than in previous two dimensional work and that the profiles are eroding profiles rather than potential (limit) profiles. It was seen that profiles develop around the offshore bar which is shaped early in the experiments. Also the depth of the summer step was found predictable from critical shear stress considerations. Finally, onshore nourishment of eroding beaches was found to be successful.
LOCAL SCOUR AMD CURRENT AROUND A POROUS BREAKWATER
Authors: Hotta Shintaro , Marui Nobuo
Published: June 2019

Scour at the foot of vertical homogeneous crib style walls which were used as models for detached breakwaters, and the rise of mean water level in the shoreside region of the breakwaters were experimentally investigated, and the experimental results were compared to some field data.