scholarly journals WAVE RUN-UP ON A NATURAL BEACH

1988 ◽  
Vol 1 (21) ◽  
pp. 10
Author(s):  
Mitsuo Takezawa ◽  
Masaru Mizuguchi ◽  
Shintaro Hotta ◽  
Susumu Kubota
Keyword(s):  
Surf Zone ◽  
Wave Theory ◽  
Transformation Model ◽  
Wave Transformation ◽  
Electromagnetic Current ◽  
Swash Zone ◽  
Reflected Waves ◽  
Wave Heights ◽  
Run Up ◽  
Incident Waves

The swash oscillation, waves and water particle velocity in the surf zone were measured by using 16 mm memo-motion cameras and electromagnetic current meters. It was inferred that incident waves form two-dimensional standing waves with the anti-node in the swash slope. Separation of the incident waves and reflected waves was attempted with good results using small amplitude long wave theory. Reflection coefficient of individual waves ranged between 0.3 and 1.0. The joint distribution of wave heights and periods in the swash oscillation exhibited different distribution from that in and outside the surf zone. This indicates that simple application of wave to wave transformation model fails in the swash zone.

scholarly journals Wave Transformation in a Multi-Bar Surf Zone: Case Study of Lubiatowo (Poland)

2016 ◽  
Vol 63 (1) ◽  
pp. 19-34 ◽  
Author(s):  
Yuan-Jyh Lan ◽  
Tai-Wen Hsu ◽  
Rafał Ostrowski ◽  
Marek Szmytkiewicz
Keyword(s):  
Field Data ◽  
Surf Zone ◽  
Transformation Model ◽  
Wave Transformation ◽  
Research Station ◽  
Jump Model ◽  
Theoretical Investigations ◽  
Wave Heights

Abstract The paper presents results of field and theoretical investigations of wave transformation in the surf zone near the IBW PAN Coastal Research Station in Lubiatowo (Poland, the south Baltic Sea). The study site displays multi-bar cross-shore profiles that intensively dissipate wave energy, mostly induced by breaking. The main field data comprise wave heights and cross-shore bathymetric profiles.Wave transformation is modelled theoretically by two approaches, namely the IBW PAN phase-averaged wave transformation model and the approach based on the hydraulic jump model, developed by Hsu & Lai (2009) for hydrological situations encountered under the actual conditions of two field campaigns - in 1987 and 1996. Discrepancies between the measured data and the model results are discussed. In general, the model results are in good agreement with the in-situ observations. The comparison of the field data with the computational results concerns a part of the surf zone between about 5 m water depth and the first nearshore stable bar, where the depth amounts to ca. 1.2 m.

scholarly journals Focusing of long waves with finite crest over constant depth

2013 ◽  
Vol 469 (2153) ◽  
pp. 20130015 ◽  
Author(s):  
Utku Kânoğlu ◽  
Vasily V. Titov ◽  
Baran Aydın ◽  
Christopher Moore ◽  
Themistoklis S. Stefanakis ◽  
...  
Keyword(s):  
Source Region ◽  
Wave Theory ◽  
Long Waves ◽  
Constant Depth ◽  
Large Wave ◽  
Weakly Nonlinear ◽  
Scaling Relationships ◽  
2011 Japan Tsunami ◽  
Wave Heights ◽  
Run Up

Tsunamis are long waves that evolve substantially, through spatial and temporal spreading from their source region. Here, we introduce a new analytical solution to study the propagation of a finite strip source over constant depth using linear shallow-water wave theory. This solution is not only exact, but also general and allows the use of realistic initial waveforms such as N -waves. We show the existence of focusing points for N -wave-type initial displacements, i.e. points where unexpectedly large wave heights may be observed. We explain the effect of focusing from a strip source analytically, and explore it numerically. We observe focusing points using linear non-dispersive and linear dispersive theories, analytically; and nonlinear non-dispersive and weakly nonlinear weakly dispersive theories, numerically. We discuss geophysical implications of our solutions using the 17 July 1998 Papua New Guinea and the 17 July 2006 Java tsunamis as examples. Our results may also help to explain high run-up values observed during the 11 March 2011 Japan tsunami, which are otherwise not consistent with existing scaling relationships. We conclude that N -waves generated by tectonic displacements feature focusing points, which may significantly amplify run-up beyond what is often assumed from widely used scaling relationships.

scholarly journals RUN-UP OF PERIODIC WAVES ON BEACHES OF NON-UNIFORM SLOPE

1984 ◽  
Vol 1 (19) ◽  
pp. 23 ◽  
Author(s):  
Yoshinobu Ogawa ◽  
Nobuo Shuto
Keyword(s):  
Experimental Data ◽  
Wave Theory ◽  
Breaking Waves ◽  
Lagrangian Description ◽  
Periodic Waves ◽  
Swash Zone ◽  
Slope Method ◽  
Long Wave ◽  
Run Up ◽  
Better Than

Run-up of periodic waves on gentle or non-uniform slopes is discussed. Breaking condition and run-up height of non-breaking waves are derived "by the use of the linear long wave theory in the Lagrangian description. As to the breaking waves, the width of swash zone and the run-up height are-obtained for relatively gentle slopes (less than 1/30), on dividing the transformation of waves into dissipation and swash processes. The formula obtained here agrees with experimental data better than Hunt's formula does. The same procedure is applied to non-uniform slopes and is found to give better results than Saville's composite slope method.

scholarly journals MEASUREMENT OF INCIDENT WAVE HEIGHT IN COMPOSITE WAVE TRAINS

1974 ◽  
Vol 1 (14) ◽  
pp. 21
Author(s):  
Ake Sandstrom
Keyword(s):  
Wave Height ◽  
Incident Wave ◽  
Wave Train ◽  
Wave Length ◽  
Wave Theory ◽  
Arithmetic Mean ◽  
Reflected Waves ◽  
Wave Heights ◽  
Wave Trains ◽  
Composite Wave

A method is proposed for measurement of the incident wave height in a composite wave train. The composite wave train is assumed to consist of a superposition of regular incident and reflected waves with the same wave period. An approximate value of the incident wave height is obtained as the arithmetic mean of the wave heights measured "by two gauges separated a quarter of a wave length. The accuracy of the method in relation to the location of the gauges and the wave parameters is investigated using linear and second order wave theory. Results of the calculations are presented in diagrams.

scholarly journals Run-Up of Solitary Waves on Twin Conical Islands Using a Boussinesq Model

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Dongfang Liang ◽  
Alistair G. L. Borthwick ◽  
Jonathan K. Romer-Lee
Keyword(s):  
Numerical Model ◽  
Solitary Waves ◽  
Laboratory Data ◽  
Boussinesq Model ◽  
Reflected Waves ◽  
Wave Refraction ◽  
Local Wave ◽  
Run Up ◽  
Gap Spacing ◽  
Incident Waves

This paper investigates the interaction of solitary waves (representative of tsunamis) with idealized flat-topped conical islands. The investigation is based on simulations produced by a numerical model that solves the two-dimensional Boussinesq-type equations of Madsen and Sørensen using a total variation diminishing Lax–Wendroff scheme. After verification against published laboratory data on solitary wave run-up at a single island, the numerical model is applied to study the maximum run-up at a pair of identical conical islands located at different spacings apart for various angles of wave attack. The predicted results indicate that the maximum run-up can be attenuated or enhanced according to the position of the second island because of wave refraction, diffraction, and reflection. It is also observed that the local wave height and hence run-up can be amplified at certain gap spacing between the islands, owing to the interference between the incident waves and the reflected waves between islands.

scholarly journals IRREGULAR WAVE TRANSFORMATION AFFECTED BY OPPOSING CURRENTS

1986 ◽  
Vol 1 (20) ◽  
pp. 53
Author(s):  
Shigeki Sakai ◽  
Kouestu Hiyamizu ◽  
Hiroshi Saeki
Keyword(s):  
Wave Height ◽  
Present Model ◽  
Surf Zone ◽  
Transformation Model ◽  
Irregular Waves ◽  
Wave Transformation ◽  
Irregular Wave ◽  
Sea Bed ◽  
Dimensionless Unit ◽  
Deep Water Wave

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.

scholarly journals WAVE RUN-UP OBSERVATION AND 2DV NUMERICAL INVESTIGATION ON BEACHES PROTECTED BY STRUCTURES

2012 ◽  
Vol 1 (33) ◽  
pp. 20
Author(s):  
Renata Archetti ◽  
Maria Gabriella Gaeta
Keyword(s):  
Numerical Models ◽  
Wave Spectrum ◽  
Low Frequency ◽  
Swash Zone ◽  
Flow Motion ◽  
Transmission Area ◽  
Wave Conditions ◽  
Run Up ◽  
Incident Waves

The main parameter for the assessment of coastal vulnerability and sediment transport is the wave run-up on the beach, defining the limit of maximum flooding, but also hydrodynamic properties in the Swash Zone (SZ) are trivial for the comprehension of hydro-morphodynamic processes. Several studies have been carried out on the SZ but few literature is still available on the run-up and on SZ flows on beaches protected by Low Crested Structures (LCSs), where flow motion is driven by a combination of low frequency infra-gravity waves and incident waves. In presence of breakwaters, swash incident waves are transmitted through the structure. In the transmission area behind the structures, wave energy is shifted to higher frequencies with respect to the incident wave spectrum and in general its mean period considerably decreases with respect to the incident one. Collecting in situ run-up measurements during storms is essential to understand the SZ processes and properly calibrate their both empirical and numerical models but measuring extreme run-up is difficult, due to the severe sea conditions and due to unexpected nature of storms. The present paper present a numerical and experimental analysis of the wave run-up and of the flow properties on a beach: the study shows the different behavior of unprotected and protected beach, subjected to the same wave conditions. In particular the paper shows that submerged breakwaters reduce in general the run-up height, on the basis of the calibrated 2DV numerical simulations, under extreme wave conditions (TR >50 years), the effect of submerged breakwaters seems to be negligible on the run-up height. Moreover a preliminary empirical equation for run-up with protected beach is proposed

scholarly journals MEASUREMENTS OF SURFACE KINEMATICS AND TEMPERATURE IN THE SURF AND SWASH ZONES USING INFRARED IMAGE VELOCIMETRY

2012 ◽  
Vol 1 (33) ◽  
pp. 55
Author(s):  
Zhi-Cheng Huang ◽  
Kao-Shu Hwang ◽  
Luc Lenain ◽  
W. Kendall Melville ◽  
Hwung-Hwang Hwung
Keyword(s):  
Water Surface ◽  
Large Scale ◽  
Surf Zone ◽  
Thermal Structure ◽  
Infrared Image ◽  
Breaking Waves ◽  
Electromagnetic Current ◽  
Correlation Algorithm ◽  
Image Velocimetry ◽  
Run Up

High intensity air bubbles generated in the surf zone and the thinning of swash flow make velocity measurements particularly challenging in coastal areas. These facts have led the need for a new measurement technique to quantify the surf and swash flow dynamics. Here, we tested infrared image techniques to measure the surface temperature and then to derive the velocity fields using cross-correlation algorithm for large-scale solitary waves breaking in the surf and swash zones. From the comparison with unspiked electromagnetic current meter (EMCM) data and previous validation, it is suggested that the infrared image velocimetry (IRIV) is satisfactory to quantify the surface turbulent flow in the surf and swash zones. The data obtained in the experiment provides a new description of surface thermal structure and kinematics for solitary breaking waves. Two-dimensional organized streaks of temperature structures are evident on the water surface behind the head of rebounding jet. Wavenumber spectrum analysis shows that the directionality of these thermal signatures evolves with time. Evolution of vorticity on the water surface during the run-up and run-down process of the solitary broken wave is discussed.

scholarly journals TRANSMISSION OF REGULAR WAVES PAST FLOATING PLATES

1974 ◽  
Vol 1 (14) ◽  
pp. 112
Author(s):  
Uygur Sendil ◽  
W.H. Graf
Keyword(s):  
Water Depth ◽  
Wave Length ◽  
Wave Theory ◽  
Finite Amplitude ◽  
Linear Wave ◽  
Regular Waves ◽  
Transmission Coefficients ◽  
Wave Flume ◽  
Wave Heights ◽  
Incident Waves

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

scholarly journals WAVE HEIGHT DISTRIBUTION AND WAVE GROUPING IN SURF ZONE

1982 ◽  
Vol 1 (18) ◽  
pp. 4 ◽  
Author(s):  
Hajime Mase ◽  
Yuichi Iwagaki
Keyword(s):  
Wave Height ◽  
Surf Zone ◽  
Irregular Waves ◽  
Wave Transformation ◽  
Height Distribution ◽  
Frequency Distributions ◽  
Irregular Wave ◽  
Wave Height Distribution ◽  
Wave Heights ◽  
Deep Water Wave

The main purpose of this paper is to propose a model for prediction of the spatial distributions of representative wave heights and the frequency distributions of wave heights of irregular waves in shallow-water including the surf zone. In order to examine the validity of the model, some experiments of irregular wave transformation have been made. In addition, an attempt has been made to clarify the spatial distribution of wave grouping experimentally. Especially the present paper focuses finding the effects of the bottom slope and the deep-water wave steepness on the wave height distribution and wave grouping.

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