scholarly journals DEFORMATION UP TO BREAKING OF PERIODIC WAVES ON A BEACH

1976 ◽  
Vol 1 (15) ◽  
pp. 26 ◽  
Author(s):  
Ib A. Svendson ◽  
J. Buhr Hansen
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
Wave Length ◽  
Empirical Relation ◽  
Breaking Point ◽  
Periodic Waves ◽  
Depth Ratio ◽  
Surface Profiles ◽  
Deep Water Wave ◽  
Sloping Beach

An experimental description is presented for 'the transformation of periodic waves which approach breaking on a gently sloping beach. The data include the variation of wave height, phase velocity, wave surface profiles, and the maximum value of the wave height to water depth ratio (H/h)max around the breaking point. The results are compared with the theories of sinusoidal and cnoidal wave shoaling, and the latter is shown in most cases to agree remarkably well when the laminar energy loss along the walls and bottom of the wave tank is included. An empirical relation is established between wave length to water depth ratio L/h at the breaking point and the deep water wave steepness H0/L0. Also the maximum wave height to water depth ratio at breaking shows considerably less scattering than found previously, when plotted versus S = hx L/h, hx being bottom slope.

scholarly journals EXPERIMENTAL INVESTIGATIONS OF PERIODIC WAVES NEAR BREAKING

1980 ◽  
Vol 1 (17) ◽  
pp. 14 ◽  
Author(s):  
J. Buhr Hansen
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
Wave Length ◽  
Experimental Investigations ◽  
Periodic Waves ◽  
Wave Energy Flux ◽  
Surface Profiles ◽  
Series Of Experiments ◽  
Sloping Beach ◽  
Theory And Experiments

The results presented are from a series of experiments of periodic waves approaching breaking on a gently sloping beach. The recorded surface profiles are compared with a cnoidal theory taking into account the effect of the bottom slope. In both theory and experiments a skewness of the profile is observed. A fair agreement is found within certain limits of the wave height to water depth ratio and when the slope is sufficiently gentle. The change in water depth over a wave length must be sufficiently small. The detailed analysis of the surface profiles including the skewness element shows good agreement with the cnoidal theory in cases where the wave height variation is as predicted by cnoidal wave shoaling. The recorded surface profiles together with the recorded phase velocities are further used in computing the wave energy flux based on the theoretical relations from linear and cnoidal theories. Reasonable constancy is observed over the whole length covered by the experiments. Finally the recorded wave set-down is compared with the results of linear and cnoidal theories. When approaching breaking neither of the theories can apparently predict the recorded water level changes.

Prediction of Water Wave Breaking Height and Depth Using ANFIS

2011 ◽  
Author(s):  
Ehsan Delavari ◽  
Ahmad Reza Mostafa Gharabaghi ◽  
Mohammad Reza Chenaghlou
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
Fuzzy Inference System ◽  
Wave Breaking ◽  
Fuzzy Inference ◽  
Breaking Point ◽  
Empirical Equations ◽  
Anfis Model ◽  
Inference System ◽  
Semi Empirical

Wave height as well as water depth at the breaking point are two basic parameters which are necessary for studying coastal processes. In this paper, the application of Fuzzy Inference System (FIS) and Adaptive Neuro-Fuzzy Inference System (ANFIS) and semi-empirical models are investigated. The data sets used in this study are published laboratory data obtained from regular wave breaking on plane, impermeable slopes collected from 22 sources. Results indicate that the developed ANFIS model provides more accurate and reliable estimation of breaking wave height, compared to semi-empirical equations. However, some of semi-empirical equations provide better predictions of water depth at the breaking point compared to the ANFIS model.

scholarly journals RANDOM BREAKING WAVES HORIZONTAL SEABED

1986 ◽  
Vol 1 (20) ◽  
pp. 68 ◽  
Author(s):  
Hans Peter Riedel ◽  
Anthony Paul Byrne
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
Breaking Waves ◽  
Random Wave ◽  
Random Waves ◽  
Flume Experiments ◽  
Depth Ratio ◽  
Wave Trains ◽  
Monochromatic Waves

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.

scholarly journals THE SOLITARY WAVE: ITS CELERITY, PROFILE, INTERNAL VELOCITIES AND AMPLITUDE ATTENUATION IN A HORIZONTAL SMOOTH CHANNEL

2000 ◽  
Vol 1 (3) ◽  
pp. 2 ◽  
Author(s):  
James W. Daily ◽  
Samuel C. Stephan, Jr.
Keyword(s):  
Solitary Wave ◽  
Wave Height ◽  
Water Depth ◽  
Wave Length ◽  
Horizontal Displacement ◽  
Smooth Channel ◽  
Amplitude Attenuation ◽  
Oscillatory Waves

The solitary wave consists of a single elevation of water above the originally undisturbed level as shown in Figure 1. It is translatory, a passing wave causing a definite net horizontal displacement of the liquid. While the characteristics of oscillatory waves depend on wave length as well as wave height and water depth, the solitary wave is apparently described completely by the wave height and water depth so long as attenuation due to friction is unimportant.

scholarly journals THE MEASURED PROPERTIES OF IRREGULAR WAVE BREAKING AND WAVE HEIGHT CHANGE AFTER BREAKING ON THE SLOPE

1988 ◽  
Vol 1 (21) ◽  
pp. 29 ◽  
Author(s):  
Akira Seyama ◽  
Akira Kimura
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
Wave Theory ◽  
Irregular Waves ◽  
Linear Wave ◽  
Periodic Waves ◽  
Zero Crossing ◽  
Irregular Wave ◽  
Height Change ◽  
Cross Waves

Wave height change of the zero-down-cross waves on uniform slopes were examined experimentally. The properties of shoaling, breaking and decay after breaking for a total of about 4,000 irregular waves of the Pierson-Moskowitz type on 4 different slopes (1/10, 1/20, 1/30 and 1/50) were investigated. The shoaling property of the zero-down-cross waves can be approximated by the linear wave theory. However, the properties of breaking and decay after breaking differ considerably from those for periodic waves. The wave height water depth ratio (H/d) at the breaking point for the zero-down-cross waves is about 30% smaller than that for periodic waves on average despite the slopes. Wave height decay after breaking also differs from that for periodic waves and can be classified into three regions, i.e. shoaling, plunging and bore regions. Experimental equations for the breaking condition and wave height change after breaking are proposed in the study. A new definition of water depth for the zero-crossing wave analysis which can reduce the fluctuation in the plotted data is also proposed.

scholarly journals Estimation of Wave-Breaking Index by Learning Nonlinear Relation Using Multilayer Neural Network

2022 ◽  
Vol 10 (1) ◽  
pp. 50
Author(s):  
Miyoung Yun ◽  
Jinah Kim ◽  
Kideok Do
Keyword(s):  
Neural Network ◽  
Wave Height ◽  
Water Depth ◽  
Wave Breaking ◽  
Water Wave ◽  
Breaking Wave ◽  
Empirical Equations ◽  
Bottom Slope ◽  
Proposed Model ◽  
Deep Water Wave

Estimating wave-breaking indexes such as wave height and water depth is essential to understanding the location and scale of the breaking wave. Therefore, numerous wave-flume laboratory experiments have been conducted to develop empirical wave-breaking formulas. However, the nonlinearity between the parameters has not been fully incorporated into the empirical equations. Thus, this study proposes a multilayer neural network utilizing the nonlinear activation function and backpropagation to extract nonlinear relationships. Existing laboratory experiment data for the monochromatic regular wave are used to train the proposed network. Specifically, the bottom slope, deep-water wave height and wave period are plugged in as the input values that simultaneously estimate the breaking-wave height and wave-breaking location. Typical empirical equations employ deep-water wave height and length as input variables to predict the breaking-wave height and water depth. A newly proposed model directly utilizes breaking-wave height and water depth without nondimensionalization. Thus, the applicability can be significantly improved. The estimated wave-breaking index is statistically verified using the bias, root-mean-square errors, and Pearson correlation coefficient. The performance of the proposed model is better than existing breaking-wave-index formulas as well as having robust applicability to laboratory experiment conditions, such as wave condition, bottom slope, and experimental scale.

scholarly journals BREAKING CRITERION ON NON-UNIFORMLY SLOPING BEACH

1986 ◽  
Vol 1 (20) ◽  
pp. 25
Author(s):  
Takashi Izumiya ◽  
Masahiko Isobe
Keyword(s):  
Experimental Data ◽  
Water Depth ◽  
Wave Period ◽  
Breaking Point ◽  
Bottom Slope ◽  
The Mean ◽  
Sloping Beach ◽  
Step Type

This paper deals with the breaker height on non-uniformly sloping beaches. A large number of experiments were carried out to obtain a breaking criterion on bar and step-type beaches. Based on the experimental data, a relationship among the breaker height, water depth, and wave period is investigated for various bottom configurations. As a result, the breaker height on non-uniformly sloping beaches is found to be well predicted by substituting an equivalent bottom slope in Goda's breaker index which has been obtained for uniformly sloping beaches. The equivalent bottom slope is defined as the mean slope in the distance of 5hg offshoreward from a breaking point, where hg denotes the water depth at the breaking point. The method for calculating the breaker height on natural beaches is also presented.

scholarly journals RESEARCHES ON DOUBLE CURTAIN WALL BREAKWATER

1966 ◽  
Vol 1 (10) ◽  
pp. 51
Author(s):  
Shigeru Tanaka
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
High Speed ◽  
Wave Length ◽  
High Tide ◽  
North Coast ◽  
Curtain Wall ◽  
Remarkable Effect ◽  
The North ◽  
Sea Bottom

It has been clarified by some researchers(R. L. Wiegel1 , F. Ursell", R. Morihira & S. Anezaki3), etc.) that the single curtain wall breakwater has no good wave-dissipating effect at the usual coastal area where the ratio of water-depth to wave-length is considerably small. The author has made researches concerning "Multiple Curtain Wall Breakwater", anticipating the supposition that it may be very effective for the dissipation of wave energy even at a shallow coastal zone, because of its peculiar effectiveness upon wave dissipation. Double curtain wall breakwater is composed of two parallel rows of curtain walls attached to the supporting props installed at an adequate interval. The interval of the said two rows is very important, and the determination of a proper interval, relating to a high wind wave having a definite length and a definite wave height, is one of the main objects of this research. These researches were mainly made experimentally. At first the author assumed that the design wave had the period of 5-6 sec, the length of 50 - 60 m and the height of 1.5 m. The results of the model experiment show that the double curtain wall breakwater, installed at the depth ranging 3 - 10 m, has remarkable effect on wave dissipation.Secondly the author selected a particular location on the north coast of Osaka Bay where the design wave has the period of 7 - 9 sec, the wave length of 65 - 70 m and the wave height of 3.8 - 4.0 m at offshore. At the expected site of thebreakwater, the sea bottom is flat and nearly horizontal, and the water depth under the condition of the extraordinary high tide is 10.5 m above the sea bottom, and an experiment was carried out by the model for this location. One kind of model was constructed in a shallow basin of 0.5 m x 25 m x 30 m, in the scale of 1 to 40 and of 1 to 70, in order to determine its transmission coefficient of wave height. Another kind of model was made in a glazed steel frame tank of 1.6 mx 1.8 m x 28 m, equipped with a piston type wave generator operated by 5 HP motor. The scale of this model is 1 to 10, and its purpose is to secure the surface disturbance and to trace the trajectories of small suspended particles by a 16 mm cine camera and a high speed motion camera.

scholarly journals EQUILIBRIUM RANGE SPECTRA IN SHOALING WATER

1970 ◽  
Vol 1 (12) ◽  
pp. 9
Author(s):  
Takeshi Ijima ◽  
Takahido Matsuo ◽  
Kazutami Koga
Keyword(s):  
Water Depth ◽  
Surf Zone ◽  
Breaking Wave ◽  
Wave Spectra ◽  
Frequency Spectra ◽  
Wave Condition ◽  
Wave Heights ◽  
Deep Water Wave ◽  
Equilibrium Range ◽  
Sloping Beach

In shoaling water on sloping beach, waves break by hydraulic instability due to the finiteness of water depth, so that frequency spectra of waves in surf zone must have any limiting form similar to the equilibrium spectrum given by Phillips(l958) In this paper, authors haze derived an equilibrium form of spectra for surf waves from the limiting wave condition at constant water depth by Miche(l944) and from breaking wave experiments on sloped bottom by Iversen(l952) The results arc compared with surf wave spectra obtained from field observations by means of stereo-type wave meter devised by the authors(1968). By means of this spectrum and by deep water wave spectra for various wind conditions, significant wave heights and optimum periods of limiting waves m surf ^one are calculated.

Surf zone transformation of wave height to water depth ratios

1992 ◽  
Vol 17 (1-2) ◽  
pp. 49-70 ◽  
Author(s):  
R.C. Nelson ◽  
J. Gonsalves
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
Surf Zone
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