Wave height, setup and currents around a detached breakwater submitted to regular or random wave forcing

1997 ◽  
Vol 31 (1-4) ◽  
pp. 77-96 ◽  
Author(s):  
Mathieu Mory ◽  
Luc Hamm
Keyword(s):  
Wave Height ◽  
Random Wave ◽  
Wave Forcing

scholarly journals Wave Interaction with Single and Twin Vertical and Sloped Slotted Walls

2020 ◽  
Vol 8 (8) ◽  
pp. 589
Author(s):  
Mohamad Alkhalidi ◽  
Noor Alanjari ◽  
S. Neelamani
Keyword(s):  
Energy Dissipation ◽  
Transmission Coefficient ◽  
Wave Height ◽  
Wave Reflection ◽  
Wave Length ◽  
Wave Interaction ◽  
Wave Transmission ◽  
Random Wave ◽  
Dissipation Coefficient ◽  
Energy Dissipation Coefficient

The interaction between waves and slotted vertical walls was experimentally studied in this research to examine the performance of the structure in terms of wave transmission, reflection, and energy dissipation. Single and twin slotted barriers of different slopes and porosities were tested under random wave conditions. A parametric analysis was performed to understand the effect of wall porosity and slope, the number of walls, and the incoming relative wave height and period on the structure performance. The main focus of the study was on wave transmission, which is the main parameter required for coastal engineering applications. The results show that reducing wall porosity from 30% to 10% decreases the wave transmission by a maximum of 35.38% and 38.86% for single and twin walls, respectively, increases the wave reflection up to 47.6%, and increases the energy dissipation by up to 23.7% on average for single walls. For twin-walls, the reduction in wall porosity decreases the wave transmission up to 26.3%, increases the wave reflection up to 40.5%, and the energy dissipation by 13.3%. The addition of a second wall is more efficient in reducing the transmission coefficient than the other wall parameters. The reflection and the energy dissipation coefficients are more affected by the wall porosity than the wall slope or the existence of a second wall. The results show that as the relative wave height increases from 0.1284 to 0.2593, the transmission coefficient decreases by 21.2%, the reflection coefficient decreases by 15.5%, and the energy dissipation coefficient increases by 18.4% on average. Both the transmission and the reflection coefficients increase as the relative wave length increases while the energy dissipation coefficient decreases. The variation in the three coefficients is more significant in deep water than in shallower water.

scholarly journals STATISTICAL PROPERTIES OF RANDOM WAVE GROUPS

1980 ◽  
Vol 1 (17) ◽  
pp. 175 ◽  
Author(s):  
Akira Kimura
Keyword(s):  
Wave Height ◽  
Transition Probabilities ◽  
Probability Distributions ◽  
Group Formation ◽  
Rayleigh Distribution ◽  
Statistical Properties ◽  
Wave Period ◽  
Random Wave ◽  
Random Waves ◽  
Resonant Wave

This study deals with the statistical properties of the group formation of random waves determined by the zero-up-cross method. Probability distributions about (1) the run of high waves (2) the total run (3) the run of resonant wave period are derived theoretically providing that the time series of wave height and wave period form the Markov chain. Transition probabilities are given by the 2-dimensional Rayleigh distribution for the wave height train and the 2-dimensional Weibull distribution for the wave period train. And very good agreements between data and the theoretical distributions have been obtained. Then the paper discusses those parameters which affect the statistical properties of the runs and shows that the spectrum peakedness parameter for the. run of wave height and the spectrum width parameter for the run of wave period are the most predominant.

scholarly journals Internal Variability of the Winter Stratosphere. Part II: Time-Dependent Forcing

2008 ◽  
Vol 65 (7) ◽  
pp. 2375-2388 ◽  
Author(s):  
R. K. Scott ◽  
L. M. Polvani ◽  
D. W. Waugh
Keyword(s):  
Lower Boundary ◽  
Polar Vortex ◽  
Internal Variability ◽  
Time Dependent ◽  
Random Wave ◽  
Frequency Locking ◽  
Wave Forcing ◽  
Wave Flux ◽  
Time Periodic ◽  
Zero Time

Abstract This paper considers the effect of time-dependent lower boundary wave forcing on the internal variability found to appear spontaneously in a stratosphere-only model when the forcing is perfectly steady. While the time-dependent forcing is found to modulate the internal variability, leading in some cases to frequency locking of the upper-stratospheric response to the forcing, the temporal and spatial structure of the variability remains similar to the case when the forcing is time independent. Experiments with a time-periodic modulation of the forcing amplitude indicate that the wave flux through the lower boundary is only partially related to the instantaneous forcing, but is more significantly influenced by the condition of the polar vortex itself. In cases of purely random wave forcing with zero time mean, the stratospheric response is similar to that obtained with steady forcing of magnitude equal to the root-mean-square of the time-varying forcing.

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 Wave-Driven Circulation of a Coastal Reef–Lagoon System

2009 ◽  
Vol 39 (4) ◽  
pp. 873-893 ◽  
Author(s):  
Ryan J. Lowe ◽  
James L. Falter ◽  
Stephen G. Monismith ◽  
Marlin J. Atkinson
Keyword(s):  
Wave Height ◽  
Incident Wave ◽  
Surf Zone ◽  
Frictional Resistance ◽  
Morphological Properties ◽  
Wave Setup ◽  
Wave Forcing ◽  
Kaneohe Bay ◽  
Reef Lagoon ◽  
Lagoon System

Abstract The response of the circulation of a coral reef system in Kaneohe Bay, Hawaii, to incident wave forcing was investigated using field data collected during a 10-month experiment. Results from the study revealed that wave forcing was the dominant mechanism driving the circulation over much of Kaneohe Bay. As predicted theoretically, wave setup generated near the reef crest resulting from wave breaking established a pressure gradient that drove flow over the reef and out of the two reef channels. Maximum reef setup was found to be roughly proportional to the offshore wave energy flux above a threshold root-mean-square wave height of 0.7 m (at which height setup was negligible). On the reef flat, the wave-driven currents increased approximately linearly with incident wave height; however, the magnitude of these currents was relatively weak (typically <20 cm s−1) because of (i) the mild fore-reef slope of Kaneohe Bay that reduced setup resulting from a combination of frictional wave damping and its relatively wide surf zone compared to steep-faced reefs, and (ii) the presence of significant wave setup inside its coastally bounded lagoon, resulting from frictional resistance on the lagoon–channel return flows, which reduced cross-reef setup gradients by 60%–80%. In general, the dynamics of these wave-driven currents roughly matched predictions derived from quasi-one-dimensional mass and momentum balances that incorporated radiation stresses, setup gradients, bottom friction, and the morphological properties of the reef–lagoon system.

Statistical distribution of nonlinear random wave height

2006 ◽  
Vol 49 (4) ◽  
pp. 443-448 ◽  
Author(s):  
Yijun Hou ◽  
Peifang Guo ◽  
Guiting Song ◽  
Jinbao Song ◽  
Baoshu Yin ◽  
...  
Keyword(s):  
Wave Height ◽  
Statistical Distribution ◽  
Random Wave ◽  
Nonlinear Random Wave

scholarly journals North Sea Infragravity Wave Observations

2021 ◽  
Vol 9 (2) ◽  
pp. 141
Author(s):  
Ad J.H.M. Reniers ◽  
Remy Naporowski ◽  
Marion F. S. Tissier ◽  
Matthieu A. de Schipper ◽  
Gal Akrish ◽  
...  
Keyword(s):  
Boundary Condition ◽  
Wave Height ◽  
North Sea ◽  
Water Depth ◽  
Local Equilibrium ◽  
Potential Contribution ◽  
Wave Forcing ◽  
Dutch Coast ◽  
The North ◽  
Wave Heights

Coastal safety assessments with wave-resolving storm impact models require a proper offshore description for the incoming infragravity (IG) waves. This boundary condition is generally obtained by assuming a local equilibrium between the directionally-spread incident sea-swell wave forcing and the bound IG waves. The contribution of the free incident IG waves is thus ignored. Here, in-situ observations of IG waves with wave periods between 100 s and 200 s at three measurement stations in the North Sea in water depths of O(30) m are analyzed to explore the potential contribution of the free and bound IG waves to the total IG wave height for the period from 2010 to 2018. The bound IG wave height is computed with the equilibrium theory of Hasselmann using the measured frequency-directional sea-swell spectra as input. The largest IG waves are observed in the open sea with a maximum significant IG wave height of O(0.3) m at 32 m water depth during storm Xaver (December 2013) with a concurrent significant sea-swell wave height in excess of 9 m. Along the northern part of the Dutch coast, this maximum has reduced to O(0.2) m at a water depth of 28 m with a significant sea-swell wave height of 7 m and to O(0.1) m at the most southern location at a water depth of 34 m with a significant sea-swell wave height of 5 m. These appreciable IG wave heights in O(30) m water depth represent a lower bound for the expected maximum IG wave heights given the fact that in the present analysis only a fraction of the full IG frequency range is considered. Comparisons with the predicted bound IG waves show that these can contribute substantially to the observed total IG wave height during storm conditions. The ratio between the predicted bound- and observed total IG variance ranges from 10% to 100% depending on the location of the observations and the timing during the storm. The ratio is typically high at the peak of the storm and is lower at both the onset and waning of the storm. There is significant spatial variability in this ratio between the stations. It is shown that differences in the directional spreading can play a significant role in this. Furthermore, the observed variability along the Dutch coast, with a substantially decreased contribution of the bound IG waves in the south compared to the northern part of the Dutch coast, are shown to be partly related to changes in the mean sea-swell wave period. For the southern part of the Dutch coast this corresponds to an increased difference with the typically assumed equilibrium boundary condition although it is not clear how much of the free IG-energy is onshore directed barring more sophisticated observations and/or modeling.

scholarly journals The Wave Heights Distribution of Random Wave Based on Ocean Basin

Kapal ◽  
2020 ◽  
Vol 17 (3) ◽  
pp. 114-122
Author(s):  
Nurman Firdaus ◽  
Baharuddin Ali ◽  
Mochammad Nasir ◽  
M Muryadin
Keyword(s):  
Wave Height ◽  
Wave Spectrum ◽  
Ocean Waves ◽  
Ocean Basin ◽  
Distribution Model ◽  
Exceedance Probability ◽  
Random Wave ◽  
Theoretical Spectrum ◽  
Sea State ◽  
Wave Heights

The wave height parameter in ocean waves is one of the important information for a marine structure design. The present paper investigates the results of wave heights distribution from laboratory-generated for single sea state. Data of the random wave time series collected at the ocean basin are analyzed using the wave spectrum and compared with the theoretical spectrum in this study. The random wave data is varied with four sea states consisting of sea states 3, 4, 5 and 6 obtained from laboratory measurements. The parameter conditions of generated sea waves are represented by a value of significant wave height and wave peak period in the range of sea states. The individual wave heights data in each sea state are presented in the form of exceedance probability distribution and the predictions using a linear model. This study aims to estimate the wave heights distribution using the Rayleigh and Weibull distribution model. Furthermore, the accuracy of the wave heights distribution data's prediction results in each sea state has been compared and examined for both models. The applied linear models indicate similar and reasonable estimations on the observed data trends.

Experimental Investigation of Wave Runup on Offshore Intake Wells in a Random Wave Environment

2019 ◽  
Author(s):  
V. Prabu Kumar ◽  
R. Sundaravadivelu ◽  
K. Murali
Keyword(s):  
Free Surface ◽  
Surface Water ◽  
Wave Height ◽  
Large Volume ◽  
Sea Water ◽  
Random Wave ◽  
Outer Face ◽  
Intake System ◽  
Diffraction Wave ◽  
Run Up

Abstract The seawater intake system is one of the essential operational units in many industries located in the coastal regions. The selection of the type of intake system to a specific sector depends on the total volume required and the quality of the sea water. The offshore seawater intake wells are a suitable option to meet the large volume water requirement and desired water quality. Sometimes two or more intake wells are installed to supply the large volume of the sea water. Since the increase in spacing between the wells leads to an increase in capital cost, it is predominant important to find the optimum distance between the wells. The present study focuses on the external and internal hydrodynamics of two caisson type offshore intake wells situated in random wave environment. Two wells are fabricated in 1:20 model scale and installed in the shallow wave basin and exposed to the random waves. The outer to outer face distance between two wells changed by concerning the outer diameter (D) of the well such that 1D, 1.5D and 2D. The wave run-up, diffraction wave height and free surface water oscillations inside the wells are measured. The distance between the two intake wells has a significant role in wave run-up and free surface oscillation inside the well. Besides, the H/d have a substantial influence on the wave run-up on the seaward face compared to the side and shoreward face in all three cases. Also, the diffraction wave height is minimum when the wells are separated by 1.5D distance. Moreover, wave run-up and free surface water oscillation are optimum when the separation distance between the wells is 1.5D.

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