scholarly journals A MODEL STUDY OF THE DISTRIBUTION OF RUN-UP OF WIND-GENERATED WAVES ON SLOPING SEA WALLS

1968 ◽  
Vol 1 (11) ◽  
pp. 56 ◽  
Author(s):  
Norman B. Webber ◽  
Geoffrey N. Bullock
Keyword(s):  
Wind Wave ◽  
Wave Flume ◽  
Model Study ◽  
Wind Velocities ◽  
Wave Heights ◽  
Instantaneous Values ◽  
Statistical Relationships ◽  
Run Up ◽  
The Relationship ◽  
The Waves

The behaviour of wind-generated waves on impermeable slopes of 1:2, 1:4 and 1:10 was investigated in a 40 ft long laboratory wind-wave flume. Apparatus for measuring instantaneous values of the run-up was devised. Wind velocities of up to 44 ft/sec were applied, producing wave heights of up to 2.5 in. Distributions were obtained for the wave and run-up characteristics. The empirical results were compared with theoretical statistical relationships. A comparison was made with the run-ups in paddle-wave experiments. The relationship between the waves and their run-ups was further investigated by a comparison of simultaneous recordings, using the methods of spectral analysis.

Study of a Wave Absorber in Various Distance Placed in a Sinusoidal Propagate Wave

2013 ◽  
Vol 302 ◽  
pp. 326-331 ◽  
Author(s):  
Zhen Zhong Yuan ◽  
Bhupendra Singh Chauhan ◽  
Hee Chang Lim
Keyword(s):  
Wind Wave ◽  
Wave Length ◽  
Ocean Waves ◽  
Floating Body ◽  
Environmental Condition ◽  
Wave Flume ◽  
Strong Source ◽  
Wave Heights ◽  
Ocean Environment ◽  
Fundamental Equations

Since there has been a rapid progress to understand the dynamics of an offshore floating body under an ocean environment, we undertake to generate the ocean waves in a lab-scale wind-wave flume. The study is aiming to observe and optimize the similar ocean environmental condition as input wave and to reduce the wall reflective wave. Several absorption methods are suggested to optimize the propagate wave by measuring the maximum and minimum of the standing wave envelope. There has been no optimized absorption method, as they highly depend on the wave period and the wave length. One of the methods - two fixed wave gauges measuring two wave heights and one wave phase - is applied in this study. In the present paper various approaches were used to analyze the results using the flume, by position of probes, with absorber and without absorber, different position, condition and angle of the wave absorber, This paper also focuses on the analysis of fundamental equations which describe the separating method of the incident and reflective wave, and finally we confirm that the wave absorber is highly efficient considering all the permutation and combination.From the study it is clear that there is a change in the wave amplitude at the receiving end then the generated end; wave absorber is a strong source to control the energy of the coming wave. With the changing the period of the wave, the reflectance is increasing when the period becomes larger.

LARGE SCALE EXPERIMENTS ON EVOLUTION AND RUN-UP OF BREAKING SOLITARY WAVES

2007 ◽  
Vol 01 (03) ◽  
pp. 257-272 ◽  
Author(s):  
KAO-SHU HWANG ◽  
YU-HSUAN CHANG ◽  
HWUNG-HWENG HWUNG ◽  
YI-SYUAN LI
Keyword(s):  
Solitary Wave ◽  
Wave Height ◽  
Solitary Waves ◽  
Water Depth ◽  
Large Scale ◽  
Scale Effects ◽  
Wave Heights ◽  
Run Up ◽  
Hydraulics Laboratory ◽  
The Waves

The evolution and run-up of breaking solitary waves on plane beaches are investigated in this paper. A series of large-scale experiments were conducted in the SUPER TANK of Tainan Hydraulics Laboratory with three plane beaches of slope 0.05, 0.025 and 0.017 (1:20, 1:40 and 1:60). Solitary waves of which relative wave heights, H/h0, ranged from 0.03 to 0.31 were generated by two types of wave-board displacement trajectory: the ramp-trajectory and the solitary-wave trajectory proposed by Goring (1979). Experimental results show that under the same relative wave height, the waveforms produced by the two generation procedures becomes noticeably different as the waves propagate prior to the breaking point. Meanwhile, under the same relative wave height, the larger the constant water depth is, the larger the dimensionless run-up heights would be. Scale effects associated with the breaking process are discussed.

scholarly journals THE RELATIONSHIP BETWEEN WAVE ACTION AND BEACH PROFILE CHARACTERISTICS

2011 ◽  
Vol 1 (7) ◽  
pp. 14 ◽  
Author(s):  
P.H. Kemp
Keyword(s):  
Rational Design ◽  
Break Point ◽  
Coarse Sand ◽  
Beach Erosion ◽  
Beach Profile ◽  
Model Study ◽  
Materials Used ◽  
Profile Characteristics ◽  
The Relationship ◽  
The Waves

The rational design of coast protection works requires a knowledge of the behaviour of the beach under natural conditions. The understanding of the relationship between the waves acting on the beach and the characteristics of the beach profile produced, is thus a necessary preliminary to the analysis of the causes of beach erosion and the evaluation of the effect of projected remedial measures. The present paper describes the results of a series of preliminary hydraulic model experiments carried out by the author prior to a model study of the behaviour of groynes in stabilising beaches. Most of the beach materials used represented coarse sand or shingle in nature. The results demonstrate the fundamental importance of the "phase difference" in terms of wave period between the break-point and the limit of uprush, in relation to flow conditions, cusp formation, and the change from "step" to "bar" type profiles. Within the limits of the experiments an expression connecting the breaker height, beach profile length, and grain diameter is developed, and its implications examined in relation to beach slope, and to the previous "wave steepness" criterion for the change from step to bar type profiles. Observations are included on the rate of recession of a shoreline due to the onset of more severe wave conditions.

On the dispersion relation of random gravity waves. Part 2. An experiment

1979 ◽  
Vol 92 (4) ◽  
pp. 731-749 ◽  
Author(s):  
Hisashi Mitsuyasu ◽  
Yi-Yu Kuo ◽  
Akira Masuda
Keyword(s):  
Gravity Waves ◽  
Wind Wave ◽  
Linear Array ◽  
Two Dimensional ◽  
Random Waves ◽  
Angular Dispersion ◽  
Wave Flume ◽  
Phase Velocities ◽  
Spectral Components ◽  
The Waves

Random waves are generated by wind in the first half of a wind-wave flume. The latter half of the flume is kept free from wind to measure the waves unaffected by the wind and wind-generated current. The random waves in the latter area are measured with a linear array of wave gauges, and their phase velocities and coherences are determined by a usual technique of the cross-spectral analysis. The measured results are compared with the nonlinear theory of two-dimensional random waves, which has been presented in part 1 of this paper (Masuda, Kuo & Mitsuyasu 1979). Agreement between the theory and the experiment is satisfactory, and observed characteristics of the phase velocity and coherence of the spectral components can be attributed to the effects of the nonlinearity and angular dispersion of the random waves.

Wind-induced growth of water waves

1982 ◽  
Vol 123 ◽  
pp. 425-442 ◽  
Author(s):  
H. Mitsuyasu ◽  
T. Honda
Keyword(s):  
Growth Rate ◽  
Water Waves ◽  
Friction Velocity ◽  
Wind Wave ◽  
Wind Waves ◽  
Pure Water ◽  
Wave Flume ◽  
Wind Speeds ◽  
Wind Profiles ◽  
The Waves

Spatial growth of mechanically generated water waves under the action of wind has been measured in a laboratory wind-wave flume both for pure water and for water containing a surfactant (sodium lauryl sulphate, concentration 2.6 × 10−2%). I n the latter case, no wind waves develop on the surface of the mechanically generated waves as well as on the still water surface for wind speeds up to U10≈ 15 m/s, where U10 is the wind velocity at the height Z = 10 m. Therefore we can study the wind-induced growth of monochromatic waves without the effects of co-existing short wind waves. The mechanically generated waves grew exponentially under the action of the wind, with fetch in both cases. The measured growth rate β for the pure water can be fitted by β/f = 0.34(U*/C)2 0.1 [lsime ] U*/C [lsime ] 1.0, where f is the frequency of the waves, C is the corresponding phase velocity, and U, is the friction velocity obtained from vertical wind profiles. The effect of the wave steepness H/L on the dimensionless growth rate β/f is not clear, but seems to be small. For water containing the surfactant, the measured growth rate is smaller than that for pure water, but the friction velocity of the wind is also small, and the above relation between β/f and U*/C holds approximately if the measured friction velocity U* is used for the relation.

scholarly journals Reduction of maximum tsunami run-up due to the interaction with beachfront development – application of single sinusoidal waves

2013 ◽  
Vol 1 (2) ◽  
pp. 1119-1171 ◽  
Author(s):  
N. Goseberg
Keyword(s):  
Long Waves ◽  
Similarity Parameter ◽  
Beach Slope ◽  
Wave Flume ◽  
Concrete Blocks ◽  
Run Up ◽  
Tsunami Run Up ◽  
The Waves ◽  
Development Application ◽  
Horizontal Bottom

Abstract. Experiments are presented that focus on the interaction of single sinusoidal long waves with beachfront development on the shore. A pump-driven methodology is applied to generate the tested waves in the wave flume. The approaching waves firstly propagate over a horizontal bottom, then climbing up a 1 in 40 beach slope. The experiments reported here are confined to the surf similarity parameter of the waves ranging from ξ = 7.69 − 10.49. The maximum run-up of the tested waves under undisturbed conditions agrees well with analytical results of Madsen and Schäffer (2010). Beachfront development is modelled with cubic concrete blocks (macro-roughness (MR) elements). The obstruction ratio, the number of element rows parallel to the shoreline as well as the way of arranging the MR elements influences the overall reduction of maximum run-up compared to the undisturbed run-up conditions. Staggered and aligned as well as rotated and non-rotated arrangements are tested. As a result, nomograms are finally compiled to depict the maximum run-up reduction over the surf similarity parameter.

scholarly journals EXPERIMENTAL STUDY OF WIND WAVES GENERATED ON CURRENTS

1978 ◽  
Vol 1 (16) ◽  
pp. 42
Author(s):  
Hajime Kato ◽  
Hiroichi Tsuruya
Keyword(s):  
Wind Wave ◽  
Wind Waves ◽  
Water Current ◽  
Pump System ◽  
Frequency Wave ◽  
Wave Channel ◽  
Wave Heights ◽  
Significant Wave Heights ◽  
True Frequency ◽  
The Waves

This paper presents some experimental results of wind waves generated on currents in a wind-wave channel with a water circulation pump system. The waves were measured at fetches less than 27.8 m by using resistance-type wave gauges. Surface velocities as well as velocity profiles in water were also measured elaborately and true frequency wave spectra were obtained from observed apparent spectra which were modified by the doppler effect of current. Significant wave heights Hwj computed from r)2 and peak frequencies of true spectra fprn were examined with emphasis. It was inferred from the variation of true spectra that the most prominent effect of water current is to change the effective fetch length. Then an idea of equivalent fetch length was proposed to express the current effect on the development of total wave energy. By using the equivalent fetch F' in place of the natural fetch it is shown that Hj/3 and fQm measured under various current conditions can be represented by the non-dimensional fetch relations, respectively, which were originally obtained in the case of no current.

scholarly journals Reduction of maximum tsunami run-up due to the interaction with beachfront development – application of single sinusoidal waves

2013 ◽  
Vol 13 (11) ◽  
pp. 2991-3010 ◽  
Author(s):  
N. Goseberg
Keyword(s):  
Long Waves ◽  
Practical Application ◽  
Similarity Parameter ◽  
Wave Flume ◽  
Concrete Blocks ◽  
Run Up ◽  
Tsunami Run Up ◽  
The Waves ◽  
Development Application ◽  
Horizontal Bottom

Abstract. Experiments are presented that focus on the interaction of single sinusoidal long waves with beachfront development on the shore. A pump-driven methodology is applied to generate the tested waves in the wave flume. The approaching waves firstly propagate over a horizontal bottom, then climbing up a 1 in 40 beach slope. The experiments reported here are confined to the surf similarity parameter of the waves ranging from ξ =7.69–10.49. The maximum run-up of the tested waves under undisturbed conditions agrees well with analytical results of of Madsen and Schäffer (2010). Beachfront development is modelled with cubic concrete blocks (macro-roughness (MR) elements). The obstruction ratio, the number of element rows parallel to the shoreline as well as the way of arranging the MR elements influences the overall reduction of maximum run-up compared to the undisturbed run-up conditions. Staggered and aligned as well as rotated and non-rotated arrangements are tested. As a result, nomograms are finally compiled to depict the maximum run-up reduction over the surf similarity parameter. In addition, some guidance on practical application of the results to an example location is given.

scholarly journals EXPERIMENTAL DATA ON THE OVERTOPPING OF SEAWALLS BY WAVES

2011 ◽  
Vol 1 (7) ◽  
pp. 36
Author(s):  
A. Paape
Keyword(s):  
Wave Height ◽  
Know How ◽  
The Past ◽  
Maximum Value ◽  
Wave Heights ◽  
Run Up ◽  
Materials Used ◽  
The Stability ◽  
The Waves ◽  
Made In

In the past it has been found that serious damage and breaching of seawalls is most frequently caused by overtopping. Hence for the design of seawalls data must be available about the overtopping by waves of the different profiles that might be possible. Naturally the conditions under which damage is caused to the seawall also depend on the type of construction and the materials used, for example: the stability of grass covered dikes can be endangered seriously by water flowing over the inner slope. In many designs the necessary height of a seawall has been defined such that not more than 2% of the waves overtop the crest, under chosen design conditions. This criterion has been determined on the assumption that the overtopping must remain very small. Some overtopping has to be accepted because no maximum value for wave height and wave run-up can be given, unless of course the wave height is limited by fore-shore conditions. Unfortunately this criterion gives no information about the volume and concentration of water overtopping the crest in each instance. Moreover it is of interest to know how this overtopping varies with other conditions, such as changes in the significant wave height. Information about the overtopping by waves was obtained from model investigations on simple plane slopes w^th inclinations varying from 1 : 8 to 1 : 2. The experiments were made in a windflume where wind generated waves as well as regular waves were employed. Using wind generated waves, conditions from nature regarding the distribution of wave heights could be reproduced. It appeared that the overtopping depends on the irregularity of the waves and that the same effects cannot be reproduced using regular paddle generated waves. In this paper a description of the model and the results of these tests are given. Investigations are m progress on composite slopes, including the reproduction of conditions for a seawall which suffered much overtopping but remained practically undamaged during the flood of 1953.

scholarly journals Modelling of Potential Tsunami in Makassar Strait, Indonesia: Submarine Landslide-Induced Tsunami Simulations

2021 ◽  
Author(s):  
Gugum Gumbira ◽  
Mardi Wibowo ◽  
Hanah Khoirunnisa ◽  
Shofia Karima ◽  
Widjo Kongko
Keyword(s):  
Numerical Models ◽  
Submarine Landslide ◽  
Tsunami Modelling ◽  
Maximum Value ◽  
Landslide Volume ◽  
Wave Heights ◽  
Initiation Stage ◽  
Run Up ◽  
Hazard Level ◽  
The Waves

Abstract Tsunami modelling of potential landslide-induced tsunami in Makassar Strait is carried out to quantify possible damage to the nearby cities. Two numerical models are used to represent the wave generation and propagation by using NHWAVE and FUNWAVE models, respectively. The simulations consist of a series of scenarios based on distinct size of the landslide volume. Four landslides with volume 5, 8, 70, and 200 km 3 are used as tsunami sources in the initiation stage. The sources are evenly distributed in the Strait addressing different landslide location. Maximum wave heights of 1.5 m are found in the area between Palu and Bangkir from case 1 and around Talok from case 2 simulations. The empirical run-up calculation of 7.5 m is estimated at the land for the presented wave height. The value significantly elevates the case 3 and 4 proportional to the volume values. The waves impact more than half of coastline with maximum value found in the Sulawesi side. Interestingly, wide and narrow shelf next to Kalimantan Island plays an important role in reducing the tsunami hazard level.

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