bluuebunny/crossref_metadata_2025 huggingface dataset:
POLYNOMIAL APPROXIMATION AND WATER WAVES
Authors: Fenton John D.
Published: June 2019

A different approach to the solution of water wave problems is considered. Instead of using an approximate wave theory combined with highly accurate global spatial approximation methods, as for example in many applications of linear wave theory, a method is developed which uses local polynomial approximation combined with the full nonlinear equations. The method is applied to the problem of inferring wave properties from the record of a pressure transducer, and is found to be capable of high accuracy for waves which are not too short, even for large amplitude waves. The general approach of polynomial approximation is well suited to problems of a rather more general nature, especially where the geometry is at all complicated. It may prove useful in other areas, such as the nonlinear interaction of long waves, shoaling of waves, and in three dimensional problems, such as nonlinear wave refraction and diffraction.
VERIFICATION OF THE ANALYTICAL MODEL FOR OCEAN WAVE-SOIL-CAISSON INTERACTION
Authors: McDougal William G. , Tsai Yau-Tang , Sollitt Charles K.
Published: June 2019

An analytical model for wave-soil-caisson interaction is verified by comparison with a finite element model and large scale experimental results. The analytical and finite element model estimates of the stresses and surface displacements of an elastic layer of finite thickness are in good agreement. The physical model experiments were conducted at the O.H. Hinsdale Wave Research Facility at Oregon State University. A 10-ft high, 8-ft long caisson was constructed on a bedding layer overlying 1 to 3 ft of soil. The caisson was exposed to waves with heights of 0.68 to 4.4 ft with periods of 1.77 to 8.80 sec. Experimental and analytical comparisons for porewater pressure were in agreement but the displacements were quite scattered.
WAVE FORCE AND MOVEMENT CALCULATIONS FOR A FLEXIBLE OCEAN OUTFALL PIPELINE
Authors: Pos J.D. , Russell K.S. , Zwamborn J.A.
Published: June 2019

The design process for the calculation of wave forces and movements for a flexible (plastic) ocean outfall is described. The design procedure is illustrated using a case study of the design of two High Density Polyethylene (HDPE) pipelines of 0,9 m and 1,0 m 0D (4 290 m and 5 45Q m long) constructed at Richards Bay, South Africa, to dispose of dense and buoyant effluent respectively. The pipeline anchor weights are based on the 1 in 1 year wave forces on the pipeline, implying that the pipeline is allowed to move during its design life. Special star anchor weights are used which keep the pipe clear of the bed while maintaining the stability of the pipeline. Friction tests were undertaken with a section of pipeline and two star weights, above water on concrete and sand and below water on sand, to determine realistic friction coefficients for the pipeline design. The results of these tests are summarised in this paper. It was found that the mean friction coefficient for submerged star weights on sand was 0,75. The movements of sections of the 0,9 m OD pipeline were calculated using a finite difference computer programme developed by Prof I Larsen and the results are summarised in the paper. It was found that movements of 1 to 2 m could occur under design wave conditions (50 to 100 year waves) and these were considered acceptable provided that the pipeline was not obstructed by rock outcrops.
KINEMATICS IN THE CRESTS OF STORM WAVES
Authors: Forristall George Z.
Published: June 2019

Uncertainty about kinematics in the crests of high waves has prevented random wave simulation from being accepted as a reliable method for computing wave forces for platform design. A theoretically defensible method of calculation for wave crest kinematics has been developed recently. The method produces a potential function which fits the kinematic boundary condition specified by second order wave theory and is thus named the Kinematic Boundary Condition Fitting (KBCF) method. KBCF agreed well with measurements of mechanically generated irregular waves made by a laser Doppler current meter in a wave tank. In order to obtain further data during high, short crested storm waves, instruments for the Fulmar Wave Crest Kinematics (FULWACK) experiment were installed in the North Sea early in November 1981. During a storm later in that month, good velocity measurements at heights up to 25 feet above mean water level were obtained in over 30 waves. For comparison with this data, KBCF was extended to three dimensions. Statistics of the velocities thus simulated agreed well with statistics of the measurements. KBCF has thus been verified as a accurate method for simulating the kinematics of natural storm waves.
STATISTICAL INVESTIGATIONS ON DIKE FAILURE
Authors: Roelse P. , Bakker W.T.
Published: June 2019

For the probabilistic design of dikes it is necessary to know the failure probability of the dike as function of the load of the dike (wave attack). This paper reports on the statistical analysis of the failure behaviour of the dikes around the Eastern Scheldt after the storm surge on February 1, 1953.
IMPULSIVE BREAKING WAVE FORCES ON AN INCLINED PILE EXERTED BI RANDOM WAVES
Authors: Tanimoto K. , Takahashi S. , Kaneko T. , Shiota K.
Published: June 2019

A calculation method of the impulsive breaking wave forces on piles is proposed in this paper. It is derived on the basis of experimental results with some theoretical considerations. Wave forces on a cylinder caused by both regular and irregular trains of waves are measured in a large wave flume. The experimental results are compared with the values predicted by both Wagner and Karman. In the proposed method, it is assumed that the impulsive force acts on the upper half of the pile between the still water level and the wave crest, and that the force distribution along the pile is triangular shape. The peak value in the distribution is expressed by the function of both the breaking force parameter and the inclination angle of the cylinder. The breaking force parameter is the ratio of the bottom slope to wave steepness. The time history of the impact force is given as a triangular pulse with a vertical rise. The duration time is determined as half of the value predicted by Karman's theory.
AN ANALYTICAL MODEL FOR OCEAN WAVE-SOIL-CAISSON INTERACTION
Authors: Tsai Yau-Tang , McDougal William G. , Sollitt Charles K.
Published: June 2019

An analytical model is developed to predict the soil responses induced by waves and caisson motion. The caisson is founded on a rubble bedding layer overlying a soil of finite depth. The responses are modeled by the Blot consolidation equations. Two approximations are employed to reduce mathematical difficulties: 1) a boundary layer approximation^ to decouple pore pressure and soil motion in the Blot equations and 2) a contact solution approximation for a thin elastic layer to address mixed-type boundary-value problems.
ENERGY DISSIPATION AND WAVE FORCE AT SLOTTED WALL
Authors: Urashima Saburo , Ishizuka Koichi , Kondo Hideo
Published: June 2019

The hydrodynamic coefficients are computed based on the measured total force on the single slotted wall in the wave field, or on the measured head loss in the uniform flow channel. The reflection, transmission and force coefficients on the single slotted wall are computed based on the mean values of the hydrodynamic coefficients. The correlations between these calculated values and measured values are found to be good. A design procedure of the single slotted wall is given the paper.
WAVE INTERCEPTION BY SEA-BALLOON BREAKWATER
Authors: Uwatoko Takahiko , Ijima Takeshi , Ushifusa Yukimitsu , Kojima Haruyuki
Published: June 2019

When a submerged, flexible bag is filled with air about 60~T0 % of its full volume ( it is called " sea-balloon " ), it has a stable shape with vertical axis of symmetry, on which several vertical wrinkles appear with folds of membrane. If two or more such sea-balloons are arranged to the direction of wave travel and connected pneumatically, balloons are deformed periodically and the air flows reciprocally in connecting pipe, following to the fluid pressure fluctuation due to incident waves. Such a system of sea-balloon intercepts incident waves effectively ( it is called " sea-balloon breakwater "). The wave interception by the breakwater is analyzed numerically by three-dimensional boundary integral method, assuming that the fluid motions both in- and out-side of the balloon are potential and that the tension in balloon membrane is proportional to the apparent elongation of membrane with virtual elastic constant. After analysis and experiments, it is made clear that in relatively long waves the incident wave is canceled by the radiation wave which is generated by volumetric change of sea-balloons, being affected by airflow resistance in connecting pipe. In short waves, sea-balloons seem to behave like as rigid piles and the incident wave is absorbed by airflow resistance in pipe and by the turbulence of fluid motion around balloons. Moreover, the effect of gaps between sea-balloons along wave crest on wave interception for relatively long waves is expressed by a simple empirical formula, by which the transmission coefficients at various types of sea-balloon breakwater is easily estimated by twodimensional computation. For the improvement of wave interception effect and from the point of practical use, the effects of other sea-balloon breakwater system are investigated by two-dimensional computation and experiments.
COMPOSITE BREAKWATER AT TAICHUNG HARBOR, R.O.C.
Authors: Wu Chung-Chuang
Published: June 2019

The composite type breakwater used in Taichung Harbor contributes economical cross section and better consideration of drifting sand control. Also, with the plan of making caissons on the sand beach and installing caissons by using an unprecedented "Island" method, it shorten the construction period of breakwater significantly.
METHOD OF ESTIMATING THE POWER EXTRACTED BY FIXED COASTAL TYPE WAVE POWER EXTRACTORS
Authors: Yano Kenji , Kondo Hideo , Watabe Tomiji
Published: June 2019

Study is performed on a vertical flap type energy converter, "Pendulor System". The power absorbed with the system in random waves is estimated using a transfer function of absorbed power (absorption coefficient) in regular waves and wave spectrum. A boundary element technique is applied to compute the hydrodynamic problem associated with the system which is placed in regular waves. The applicability of the method has been examined by a series of field test at a test plant caisson. The agreement between estimation and experiment was found to be good except near the resonance frequency of the system.
VERIFICATION OF THE CONSEQUENCES OF WAVEDIRECTIONALITY ON THE LOADING OF LONG COASTAL STRUCTURES BY FIELD EXPERIMENTS
Authors: Van Heteren J. , Botma H.C. , Roskam A.P. , Battjes J.A.
Published: June 2019

Field measurements were done at the Haringvliet barrier to verify the theory that loading on long structures shows a considerable reduction if wave directionality is taken into account instead of calculating with uniform long crested waves. Wave loads were measured with a row of pressure meters at the barrier. Directional parameters of the incoming wave field were calculated from the signals of a 3-component acoustic current meter, mounted 7.5 meter in front of the barrier. These calculations were different from those used for an open sea, since the waves near a reflecting structure are formed by two highly correlated wave fields. The agreement between the results of the measurements and theory is good.
INNOVATIVE DETERMINATION OF NEARSHORE FLOOD FREQUENCY
Authors: Butler H. Lee , Prater Mark D.
Published: June 2019

Reliable estimates of coastal flooding from tides and storm surges are required for making sound engineering decisions regarding the design, operation and maintenance of many coastal projects. A recent investigation of flood frequency along the coast and within the bays of southern Long Island, New York, produced new and optimal approaches to obtain meaningful statistical estimates of flood levels. This paper summarizes various elements of the study and concentrates on the problem of stage-frequency computations in the inland bay areas. Methods for optimizing the number of necessary storm/tide simulations and estimating the accuracy of results are presented.
NUMERICAL SIMULATION ON THERMAL DIFFUSION CONCERNING AIR-SEA HEAT EXCHANGE EFFECTS
Authors: Chyen P.C. , Yang C.S. , Wang I.L. , Hwung H.H.
Published: June 2019

The numerical simulations on thermal diffusion always concentrated upon the raised temperature and temperature distributions after the heated water discharged from outlet into surrounding water, and the surrounding water temperature was assumed to be a constant. Actually, the water temperature on surface layer in shallow water area varies several centigrade degrees depended upon the weather conditions during a whole day. In order to obtain the absolute water temperature prepared for the ecological changes assessment and even provided for the operation basis of the cooling water system that air-sea heat exchange has to be considered in the numerical simulation of thermal discharges. For the practical application of this numerical simulation, the first nuclear power plant in Taiwan was taken as an example and simulated in this paper. And the results were presented in figures.
EFFECT OF BREAKING WAVES ON DISSOLVED OXYGEN AND ORGANIC MATTER
Authors: Hosoi Yoshihiko , Murakami Hitoshi
Published: June 2019

Water pollution in the near shore area has become a serious problem in coastal engineering. In such a situation, not only wave dissipation but also the functioning of water pollution control is expected from the coastal structure. Since breaking waves are accompanied by many bubbles and intense water turbulence, they promote the contact between organic matter and bacteria and between water and air. Therefore the water quality related to organic matter seems to change under the effect of breaking waves. In this study the variation of the dissolved oxygen and the organic matter near the surf zone were considered. First, a self purification model in the surf zone was developed. Second, the efficiency of breaking waves on reaeration and organic matter decomposition was estimated by an experiment in the laboratory flume and numerical simulation.
SHORE PROTECTION PLAN FOR THE NILE DELTA COASTLINE
Authors: Kadib A.L. , Shak A.T. , Mazen A.A. , Nadar M.K.
Published: June 2019

A Shore Protection Master Plan (SPMP) for the Nile Delta Shoreline, extending from 30 kms west of the city of Alexandria (Arab Republic of Egypt) to 30 kms east of Port Said, is developed and reported. The SPMP was developed in three stages: (1) collection and analysis of relevant data to identify existing and future coastal problems and limits of needed shore protection, (2) development of shore protection alternatives with costs and economic evaluations, and (3) detailed design and technical specifications for the selected shore protection schemes along the SPMP zone. This paper summarizes Tetra Tech, Inc./Honeywell work and achievements on this project while under contract with the Egyptian Shore Protection Authority (SPA). The SPMP considered the Egyptian Government and the SPA national needs to the year 2000.
DESIGN AND PERFORMANCE OF ARTIFICIAL BEACHES FOR THE KUWAIT WATERFRONT PROJECT
Authors: Kana Timothy W. , Al-Sarawi Mohammad , Holland Michael
Published: June 2019

One of the largest recreational waterfront projects ever designed (Sasaki Associates, 1979) is located along 20 kilometers (km) of the City of Kuwait on the Arabian Gulf (Fig. 1). Planning and design were initiated in 1976, and the first phases of construction were completed in 1985. Amenities included artificial beaches, promenades, waterfront parks, and an artificial island. Extensive armoring has also been installed, ranging from 10-ton, dolosse breakwaters to large, quarry-stone revetments. Total investment in the first two phases is upwards of US $100 million.
WAVE INTERACTION WITH MOORED SLOPING BREAKWATER
Authors: Kharaghani S. , Lee J.J.
Published: June 2019

Interaction of periodic waves with a moored inclined floating breakwater has been studied theoretically and numerically. The floating breakwater is inclined at a well defined angle with the sea bottom; its seaward end in protruding above the water surface. In static equilibrium, without incoming waves, the body weight, the buoyance force, and the restoring forces from the mooring lines which are modeled using linear springs keep the breakwater at a fixed angle. The theoretical formulation is based on a suitable variational principle. For the numerical solution a combination of finite element approximation as well as eigen function expansion technique is used. The result is obtained in terms of wave transmission and reflection coefficient as well as the sway, heave and roll motion of the breakwater. The sensitivity of the solution on the parameters such as the bottom gap size, angle of inclination, and the mooring line stiffness are investigated over a range of incident wave transmission coefficient for dimensionless wave number hk > 0.60 ( k is wave number, h is the water depth). The results suggest that a certain degree of sheltering effect can be realized by employing this type of sloping breakwater.
DIRECTIONAL SPECTRA IN CURRENT-DEPTH REFRACTION
Authors: Hirosue F. , Sakai T.
Published: June 2019

According to Brink-Kjaer et al.'s discussion(1984), the expression of the wave direction change velocity is modified in our numerical model for the directional wave spectra change due to current-depth refraction (Sakai et al., 1983). The wave reflection and breaking conditions due to current are discussed from a view point of numerical analysis. Effects of the refraction term in the modified wave action equation on the directional spectra change are examined. The relative importance of current and water depth change in the directional spectra change is also examined.
FIELD STUDIES OF BUOYANT JET IN COASTAL WATERS
Authors: Leighton Jeffrey P. , Tu Shuen-Wei Scott
Published: June 2019

Studies were made on a surface buoyant jet from a coastal power plant. The cooling water discharges into shallow waters of irregular bottom topography forming a partially enclosed embayment that connects to the open ocean. Near field mixing was found to be influenced by bottom bathymetry, lateral confinement and a large obstruction. Surface centerline temperature decay, bottom separation and the heat and mass distribution within the embayment were analyzed.
STUDIES OF TSUNAMI HAZARD
Authors: Lin I. Chen , Tung C.C.
Published: June 2019

Tsunami hazard is investigated using the indirect approach with simple seismological and hydrodynamic models. It is assumed that earthquakes of random magnitude may originate anywhere with equal likelihood from a single straight fault and the site is located on the perpendicular plane bisecting the fault. The ground displacement is instantaneous and consists of a block uplift type of movement which may be circular or elongated in the plan view. The hydrodynamic model is based on linear long wave theory wherein the ocean is of constant depth and infinite in the horizontal extent, and the earth is flat. Tsunami hazard is computed for various values of the parameters and a sensitivity study is carried out to examine the effect of certain parameters on hazard.
A THREE DIMENSIONAL MODEL OF THE GULF OF ALASKA
Authors: Liu Shiao-Kung , Leendertse Jan J.
Published: June 2019

This paper presents the development of a three dimensional model of the Gulf of Alaska. The model extends between the Vancouver Island and the Aleutian Islands covering approximatedly 1.5 million square kilometers over the northern Pacific Ocean. Formulated on an ellipsoidal horizontal grid and variable vertical grid, the model is schematized over a 81 x 53 x 10 grid structure. The solution scheme is implicit over the vertical and is programmed using one-dimensional dynamic array for the efficient use of machine storage. The turbulence closure scheme for the non-homogeneous vertical shear is formulated so that the potential and kinetic energetics are monitored and transferred in a closed form. The hydrodynamic model is coupled to a two-dimensional stochastic weather model and an oil-spill trajectory/weathering model. The former also simulates stochastically the cyclogenetic/cyclolytic processes within the modeled area. The paper also compares the computed results with the available field data. Good agreements are found in tidal amplitude and phases as well as currents.
MODEL/FIELD COMPARISON - COASTAL BUOYANT JET
Authors: Tu Shuen-Wei Scott , Ryan Patrick J. , Leighton Jeffrey P.
Published: June 2019

Calibration and verification of a 1:75 scale undistorted hydraulic model is described. The model was used to simulate the waste heat distribution in shallow and semi-confined receiving waters. The study was carried out in the laboratory by analyzing the effect of several parameters in comparisons of model and field data. Because of the shallow receiving waters, it was found that the near-field bathymetry, bottom roughness and waves were the critical parameters in achieving a reasonable simulation.
A RE-ANALYSIS OF THE SPECTRA OBSERVED IN JONSWAP
Authors: Battjes J.A. , Zitman T.J. , Holthuijsen L.H.
Published: June 2019

The frequency spectra of wind-driven waves observed during JONSWAP are re-analyzed to establish whether the Toba formulation for the highfrequency tail (~f ) fits the data better than the Phillips formulation (~f_ ) used originally in the JONSWAP project. The results indicate that the f-,*-tail provides a better fit to the observed spectra. The proportionality factor in Toba's spectrum, which is theoretically expected to be a universal constant, is found to be uncorrelated with the growth stage of the waves.
A NUMERICAL SIMULATION OF THE MOORED CONTAINER SHIP MOVEMENTS INDUCED BY WIND
Authors: Cheng T.Z. , Liang N.K.
Published: June 2019

In the past, only the ship motion due to wave is studied. This study is focused on the ship motion induced by a steady oscillating wind. The oscillating wind is assumed to be sinusoidal of a constant frequency. The wind direction 9, number of mooring lines and the wind frequency are the parameters in simulating an Evergreen's Ever Garden class container ship. The results show that the worst angle between the quay and the prevailing wind direction is 45°. Surge and roll are the most significant motions induced by the oscillating wind. By changing the number of mooring lines, the natural frequency can be kept away from the dominant wind frequency, except roll.
PHYSICAL MODEL TEST OF THE MOORED CONTAINER SHIP MOTION AND THE RELATED INDUCED MOORING FORCE
Authors: Hou H.S. , Weng G.H.
Published: June 2019

To optimize structure design it is useful to conduct detail physical model tests. Tests of various basic physical phenomena (e.g. resonance problems), reproducing a sea state of prototype duration and then from the behavior of entire structure, the optimal design to the wharf structure will be obtained. Preliminary analyses are made by basing upon experience for structure submitted to the similar action of wave or climates, combined with knowledge of available construction materials, i.e. selection of the rubber fender and the mooring system. Therefore, ship impaction force model simulation could lead to an ideal design. A lot of experimental research work is conducted in order to facilitate determination of its test value when different factors are involved. Some design recommedations are commonly based on experimental results rather than that from mathematical iterations.
SHIP MOTION STUDY FOR THE 2010 AND 2020 PLAN IN THE SAN PEDRO BAY, CALIFORNIA
Authors: Yuen A.F. , Burke M.G. , Leung T.C.
Published: June 2019

The Port of Long Beach, in cooperation with the Port of Los Angeles and the Corps of Engineers, has been working on the development of a Master Plan for the San Pedro Bay area. This Master Plan, nicknamed the "2020 Plan", is intended to project the Port's land and channel requirements through the year 2020. Any landfill expansion program would be implemented in phases throughout the life of the Master Plan. The initial phases of such a plan would greatly limit the ability of the Port to revise the future configuration of landfill phases, making it important for the Port to determine a final landfill configuration before implementing the early phases. In developing the 2020 Plan, the Port projected a need for approximately 2,600 acres of additional land. In attempting to turn this 2,600 acre figure into a landfill scheme, the controlling agencies had to take a number of factors into consideration, including (1) water quality and tidal circulation; (2) potential ship motion problems; (3) additional berths required for future development; (4) land and waterside transportation corridors required; (5) availability of dredge material for creating the land; (6) available areas for creating landfills; (7) efficiency of land usage in various configurations; (8) types of ships anticipated to use the new landfills; (9) types of terminals anticipated to be located on the new landfills. The Port of Long Beach developed two basic schemes which addressed the requirements listed above. In either case, the landfill configuration for the Port of Los Angeles remained the same. The first scheme (called the island scheme, Figure 1) had the advantage of more closely matching the proposed Port of Los Angeles development. Water quality and tidal circulation would be improved with this scheme. The second scheme (called the horseshoe scheme, Figure 2) created a channel on the Long Beach side which did not match the orientation of the channel on the Los Angeles side. This channel was better protected from wave forces than the island scheme, where ships would have to be berthed along the exposed southerly boundary.
IRREGULAR WAVE TRANSFORMATION IN A BOUSSINESO WAVE MODEL
Authors: Pruser H.H. , Schaper H. , Zielke W.
Published: June 2019

Numerical wave models for shallow water waves are of particular importance for the calculation of the wave climate in harbours and coastal areas. Especially nonlinear time domain models, which are based on the Boussinesq-Wave- Equations, may be helpful in the future for simulating the interaction of currents with refraction, diffraction, reflection and for simulating shoaling..-of irregular waves in natural areas; a potential which has not yet been fully developed. During the last ten years numerical models, based on these equations, have been published; such as ABBOTT et. al. , HAUGUEL and SCHAPER / ZIELKE . Research on this topic is currently being carried on. Some efforts have been made to verify the capability of the models to describe the various physical phenomena. However, up to now, verification has been limited to regular waves. The aim of this paper therefore is, to consider questions concerning irregular, nonlinear waves.
ON THE SQUATTING OF SHIPS IN SHALLOW AND RESTRICTED WATER
Authors: Ferguson A.M. , McGregor R.C.
Published: June 2019

A major feature of the advances in marine technology is the increasing number, size and speed of ships and, consequently, an increased interest in hydrodynamic problems associated with water restricted in depth and/or lateral extent. The transport of dangerous cargoes and their impact on the benefits of resolving the areas of uncertainty. Experience of 1,104 vessels of different flags and trades during 1978, shows that grounding/stranding is the third most frequent cause of damage[1], An examination of the total expenditure of money and time required to repair the resulting damage shows this category to rank highly in both. Indeed, the total repair cost expended as a result of this cause rank top and account for more than l/5th of the total. Although the shipowner bears a large proportion of the cost of lost revenue, grounding represents a significant cost to underwriters, shipowners and port authorities. The continuous increase in size and draught of vessels in relation to water depth ensures that this situation will continue unless there is a radical development in instrumentation. To limit the risk of grounding it is extremely important to be able to predict which of a vessel's extremities will experience the greatest sinkage and ground. Where the underkeel clearance is low, reasonable accuracy is demanded in order to ensure safety and to avoid unduly reducing the earning capacity of the vessel by overcaution. This requires a sound knowledge of a vessel's tendency to 'squat'.
ROUGH TURBULENT BOUNDARY LAYER IN SHORT-CRESTED WAVES
Authors: Hsu John R.C.
Published: June 2019

Prior to the investigation of rough turbulent boundary layer in a short-crested wave, the oscillatory laminar boundary layer at the bed is considered. Supported by numerical results of water-particle motions close to the bottom, the general patterns of kinematics in the laminar boundary layer within this wave system are reported in order to promote the understanding of the complex phenomenon. To propose a suitable method for turbulent boundary layer within such a wave system, a two-layer model using time-independent viscosity coefficient is first studied. Potential application of this model to short-crested waves is considered. From numerical results it is found that the time-invariant viscosity model is useful but can not produce velocity profile with flow reversal. It is suggested that a time-varying viscosity model may be more appropriate.
APPLICATIONS ON NONLINEAR WAVE COMBINATION
Authors: Juang J.T.
Published: June 2019

Due to the special bathymetry in Taiwan Strait, the waves off the western coast of Taiwan are considered to be composed of two-source wave system. One propagates from the central part of the Strait named main wave, and the other is generated by the local wind known as local wave which occurs along the shore. After the combination and the transformation procedure from these two-nonlinear-source wave system, the wave height distribution in Taiwan Strait should be modified. A comparison of the wave height distributions based on the present proposed method with the field data indicates that the present method yields a better result than other theorems. Furthermore, the result of application of two non-linear wave theorem to wave prediction are also presented.
MATHEMATICAL AND PHYSICAL WAVE DISTURBANCE MODELLING COMPLIMENTARY TOOLS
Authors: Berenguer I. , Madsen P.A. , Rubjerg M. , Kej A.
Published: June 2019

This paper presents comparisons between physical and numerical model reproductions on the basis of comprehensive wave disturbance studies of a major Spanish port. Mathematical modelling has reached in many cases a degree of reliability comparable to that of a physical model, but it is essential that both types of modelling systems are validated against measurements.
ESTIMATION OF WATER PARTICLE VELOCITIES OF SHALLOW WATER WAVES BY A MODIFIED TRANSFER FUNCTION METHOD
Authors: Koyama Hirofumi , Iwata Koichiro
Published: June 2019

This paper Is intended to propose a simple, yet highly reliable approximate method which uses a modified transfer function in order to evaluate the water particle velocity of finite amplitude waves at shallow water depth in regular and irregular wave environments. Using Dean's stream function theory, the linear function is modified so as to include the nonlinear effect of finite amplitude wave. The approximate method proposed here employs the modified transfer function. Laboratory experiments have been carried out to examine the validity of the proposed method. The approximate method is shown to estimate well the experimental values, as accurately as Dean's stream function method, although its calculation procedure is much simpler than that of Dean's method.
NONLINEAR THEORY ON PARTICLE VELOCITY AND PRESSURE OF RANDOM WAVES
Authors: Kuo Yi-Yu , Wang Hwar-Ming
Published: June 2019

In this paper, to the third approximation, we used the Fourierstieltjes integral rather than Fourier coefficient to develop a weakly nonlinear theory. From the theory, the nonlinear spectral components for water particle velocity and wave pressure can be calculated directly from the directional spectrum of water surface displacement. Computed results based on the nonlinear theory were compared with that of experiment made by Anastasiou (1982). Furthermore, in accordance with the different characteristics of wave properties, such as wave steepness, water depth and so on, the nonlinear effects on wave kinematic and pressure properties were extensively investigated by using some standard power spectra.
WAVE TRANSFORMATION AND MEAN SEA LEVEL VARIATION
Authors: Lin Shi-Chuan , Hwang Jeng-Shin
Published: June 2019

For the practical application in coastal engineering, the universal model of water wave, momentum conservation and energy conservation equation with considering of energy loss due to bottom friction and wave breaking is adopted in this paper to evaluate the wave transformation on general slope, which including wave shoaling, breaking and attenuation after breaking as well as wave set-up and set-down during the waves advancing toward the coast. In comparison with the results of theoretical approaches as well as experimental data accomplished by the traditional method, very good coincidence is obtained besides the mean sea level variation.
STATISTICAL MODELLING OF LONG-TERM WAVE CLIMATES
Authors: Burrows Richard , Salih Barham A.
Published: June 2019

The paper discusses the long-term statistical properties of ocean and coastal wave climates derived from the analysis of instrumental wave data. The aim of the work reported has been to determine the theoretical distributions, from those commonly used in analysis of wave data, which best describe the joint probability of significant wave height, Hs, and mean zero-upcrossing period, Tz. A method of modelling the wave climate in this manner has been developed utilizing parametric means of specification. The data base used in the study covers records from 18 sites around the British Isles.
LIMIT WAVES ON HORIZONTAL SEA FLOOR
Authors: Lu Chia-Chi , Wang John D. , Le Mehaute Bernard
Published: June 2019

A numerical solution to periodic nonlinear irrotational surface gravity waves on a horizontal sea floor is developed using an iterative Boundary Integral Equation Method (BIEM). This solution technique is subsequently applied to determine the characteristics of limit waves for which the wave crest theoretically ceases to be rounded and become angled with an included angle of 120 degrees.
WAVE GROUP PROPERTY OF WIND WAVES FROM MODULATIONAL INSTABILITY
Authors: Mase Hajime , Iwagaki Yuichi
Published: June 2019

This paper discusses wave grouping of wind waves from the physical viewpoint of wave modulational instability. Amplitude modulation periods obtained from the smoothed instantaneous wave energy history (SIWEH) of the observed data are compared with the predicted values by the modulational instability theory using the Zakharov equation for a finite constant water depth derived by Stiassnie and Shemer(1984). The modulation period normalized by the typical wave period corresponds to the length of total run. It is shown that the amplitude modulation periods of the observed data agree satisfactorily with the predicted values. Thus we conclude that the modulational instability is a hydrodynamical cause of grouping of high waves.
ON THE GROWTH OF WATER WAVES BY TURBULENT WIND
Authors: Mitsuyasu H. , Kusaba T.
Published: June 2019

The growth of water waves by turbulent wind is studied on the basis of typical results of recent studies. It is shown that the energy input from wind to a spectral component is not much affected by the existence of the other spectral components, and the dimensionless growth rate 3/f is uniquely determined by u^/c if the friction velocity u* measured over the water surface is used for the analysis. It is also shown that steep monochromatic waves without wind action show very complicated spectrum, but, under the wind action, they tend to be a continuous spectrum which has a spectral peak near the frequency of the lower side band and satisfy the 3/2 power law.
EXPERIMENTAL STUDY ON KINEMATICS AND DYNAMICS OF WAVE BREAKING
Authors: Mizuguchi Masaru
Published: June 2019

Wave breaking on a slope is one of the most important problems for the coastal engineers to be investigated. However wave breaking is a complex phenomenon which is not yet fully understood, in spite of the fact that many researches have been devoted to that subject. It is well known that waves break in different forms: spilling, plunging and surging. Untill now no theoretical explanation is given for the classification of the breaking pattern. Recently numerical simulation of wave breaking with full nonlinear governing equations based on the irrotational assumption have been developed ( Longuet-Higgins & Cokelet, 1976 and so on). The simulation results show that the spilling breaker exhibit a small scale plunging jet as Miller (1976) observed in a laboratory experiment. Most of the research works on the wave breaking are based on the laboratory experiments, in particular visual observation. Basco(1985) is the latest one on this line. Description of wave breaking based on visual observations provide limited information. Hedge & Kirkg8z(1981) report an experimental work in which the photographic approach was supplemented by the velocity measurement by Laser- Doppler Velocimeter. They found that the water particle velocity at the crest is smaller than the wave crest propagation velocity especially on steep slope beaches, and suggest that the plunging jet is not necessary formed at the crest, it is normally accepted that the flow field is irrotational before waves break. Therefore generation of vorticity as well as turbulence can be considered as eminent features of the wave breaking. Few studies are reported where velocity are measured in a fine grid of points so that the vorticity can be evaluated (Okayasu et al., 1986). There are several papers which pay an attention mainly on the structure of turbulence induced by wave breaking (Peregrine & Svendsen, 1978, Stive, 1980 and so on.) Our aims are to provide a set of experimental data of a wave breaking of plunging type on a slope, in which the velocity field is measured in detail with high accuracy, and to discuss the kinematics and dynamics based on the data set, especially from the inception of breaking through the plunging process. In view of the initiation of wave breaking, forming of the plunging jet or overturning may be essential. Peregrine (1983) gives a comprehensive study of the fluid dynamics of the wave breaking, in which some possiblities of the plunging process are discussed.
DIRECTIONAL GROWTH FOR NUMERICAL WIND WAVE MODELS
Authors: Neu W.L. , Kwon S.H.
Published: June 2019

This study is concerned with the operation of spectral wind wave models. Many spectral wind wave models use a growth mechanism which operates on the point spectrum with directionality being introduced after the fact by the use of a spreading function. It is recognized here that this approach leads to errors whenever the wind and wave fields are not aligned. This is demonstrated by comparing the performance of two first generation models under various conditions. One makes use of a point spectral growth mechanism and follows the operation of the Spectral Ocean Wave Model (SOWM). The other uses a directional growth mechanism but is otherwise the same as the first. A large difference between the models is noted for swell corrupted seas.
NUMERICAL SIMULATION OF 1964 TSUNAMI ACROSS THE PACIFIC OCEAN
Authors: Chen Michael H.
Published: June 2019

A two dimensional numerical longwave model using an appropriate open sea boundary condition has been developed. The use of the open-sea boundary condition makes it possible to simulate longwave propagation using a smaller region without covering the entire ocean. The numerical model is used to predict the arrival time of tsunamis resulting from the 1964 Alaskan earthquake at various stations with reasonable success.
VELOCITY FIELD UNDER PLUNGING WAVES
Authors: Okayasu Akio , Shibayama Tomoya , Mimura Nobuo
Published: June 2019

In order to clarify the characteristics of the velocity field in the surf zone, three sets of detailed and precise two dimensional laboratory experiments were performed. Spatial distributions and time histories of velocity were measured by using a hot film velocimeter with a split type probe or a two components laser doppler velocimeter for regular wave conditions. Typical plunging breakers were formed during the experiments. Based on the experimental results, a model was investigated in order to estimate the two dimensional distribution of the on-offshore steady current below the trough level.
IRREGULAR WAVE TRANSFORMATION AFFECTED BY OPPOSING CURRENTS
Authors: Sakai Shigeki , Hiyamizu Kouestu , Saeki Hiroshi
Published: June 2019

Transformation of irregular waves affected by opposing currents on a sloping sea bed was discussed, experimentally and theoretically. It was found that representative values of wave height, such as a significant wave height, are larger before breaking and the wave height decaying occurs more promptly in a surf zone as opposing currents become dominant, and that characteristics of a irregular wave transformation are determined by the dimensionless unit width discharge q* and the deep water wave steepness. This means that the effects of opposing currents on irregular wave transformation are qualitatively identical to that on the regular waves. A transformation model of irregular waves affected by opposing currents was presented. In the model, formulations for a regular wave transformation, in which the effects of opposing currents were taken into account, were applied to individual waves defined by zero-down" cross-method from irregular wave profiles. Comparisons between experimental results and the prediction by the model showed that the present model gives a good explanation for wave height distributions and the experimental finding that the surf zone is moved offshore by opposing currents.
EXTREME WAVE GROUPS IN STORM SEAS NEAR COASTAL WATER
Authors: Su Ming-Yang
Published: June 2019

We discuss statistics of wave groups containing the maximal wave height over wave records of 20 minutes. These wave groups are called extreme wave groups (EWGs). The concept of the EWG combines the two previously separately considered design factors of extreme waves and wave groups into a more severe storm seas wave action. The wave data used in this investigation consists of near 540 records of wave staff measurements in the Gulf of Mexico. Specifically, we shall present (a) the dependence of EWG properties on the bandwidth of wave spectra, (b) the mean envelope shape of EWGs, exhibiting distinct differences from the envelope shape of regular basis.
PRACTICAL METHOD FOR EVALUATION DIRECTIONAL SPECTRA AFTER SHOALING AND REFRACTION
Authors: Tang Frederick L.W. , Lin C.F.
Published: June 2019

Different Methods have been developed to calculate the deformation of spectrum as waves advance to the shallow water. Wave ray method is a traditional way to compute the change of wave ray after refraction. It is restricted to the regular wave. After slicing the linear spectrum, a lot of components of spectrum can be gained, and each component can be considered as a monochromatic wave. And then after the deformed components are worked out at the same point in sea, a deformed spectrum in shallow water is gained by summing up them. Therefore the wave ray method could be extended to the irregular wave in ocean. In real bathymetry, the difficulty in applying such method is to solve the wave ray which must pass through the assigned point. In this paper, calculation approach as well as computer program are contrived to adopted in real bathymetry. The results of computation reveal some significant characteristics of directional spectra in shallow water. Furthermore, the statistical features of waves at the point of interest are to be evaluated.
GROUPING WAVES AND THEIR EXPRESSING ON ASYMPTOTIC ENVELOPE SOLITON MODES
Authors: Yasuda T. , Nakashima N. , Tsuchiya Y.
Published: June 2019

An approach, that treats natural sea states with remarkable groupiness as random sequences of envelope solitons, is suggested here to explain their dynamical and statistical properties from the viewpoint that wave packets contained in the states have their own characteristics and should be regarded as elementary modes. Some examinations are made on its applicability to the temporally observed waves. And the approach is shown to be effective also for waves with a non-zero nonlinearity and finite spectral band-width. Further, a formulation based on envelope solitons is made on the wave drifting force and is shown to be useful for analyzing the time series of drifting forces.
NEARSHORE BEHAVIOR OF BORE ON A UNIFORMLY SLOPING BEACH
Authors: Ghazali A. , Yeh Harry H.
Published: June 2019

Using the laser-induced fluorescent method, the detailed transition process from bore to run-up mode is clarified experimentally. The transition process is found to be different from the previous predictions, and might provide an explanation for the discrepancies of the run-up height between the theory and laboratory measurements. Turbulence generated in a bore appears to be highly three-dimensional and sporadic. Turbulence generated close to the shore is advected with the bore-front motion and violent turbulent actions result during the transition from bore to run-up mode.
RANDOM BREAKING WAVES HORIZONTAL SEABED
Authors: Riedel Hans Peter , Byrne Anthony Paul
Published: June 2019

According to wave theories the depth limited wave height over a horizontal seabed has a wave height to water depth ratio (H/d) of about 0.8. Flume experiments with monochromatic waves over a horizontal seabed have failed to produce H/d ratios greater than 0.55. However designers still tend to use H/d 0.8 for their design waves. Experiments have been carried out using random wave trains in the flume over a horizontal seabed. These experiments have shown that the limiting H/d ratio of 0.55 applies equally well to random waves.
INFLUENCE OF BREAKER TYPE ON SURF ZONE DYNAMICS
Authors: Arcilla A.S. , Vidaor A. , Monso J.L.
Published: June 2019

Two of the most significant variables for surf zone hydrodynamic analyses are the mean rate of wave energy dissipation, D, and the longshore current velocity, VI . A detailed theoretical model is extremely difficult to establish (definition of bottom and free surface boundaries, stochastic forcing terms, intense turbulent mixing, etc). The type and amount of existing measured values (laboratory and field) also preclude any accurate calibration, particularly for the more complex formulations. The paper, therefore, presents an average (cross-shore) comparison among state-of-the-art models for D and VI. This illustrates the dependence of these variables on the surf zone dynamic state (closely related to the beach stage, (Short, 1978)), characterized by Iribarren's parameter, ir. Well defined relationships with Ir are obtained for these variables. An expansion of the range of validity of certain models is also attained by calibration of their characteristic free parameters as functions of Ir using a large set of field and laboratory data, and by comparing their general expresion with that of (Losada and S.Arcllla, 1985), which does not include any free parameter. Therefore, theoretical laws for D and VI as simple functions of beach, wave and dynamic state parameters are presented, together with an improved estimation of the empirical coefficients appearing in the various models, suitable for prediction in all ranges of Ir, even though data on the collapsing-surging range are scarce and should require further calibration.