Violent Motion as Near Breaking Waves Meet a Vertical Wall

1992 ◽  
pp. 291-297 ◽  
Author(s):  
M. J. Cooker ◽  
D. H. Peregrine
Keyword(s):  
Vertical Wall ◽  
Breaking Waves

Extreme long waves over a varying bathymetry

2019 ◽  
Vol 878 ◽  
pp. 481-501 ◽  
Author(s):  
James G. Herterich ◽  
Frédéric Dias
Keyword(s):  
Conformal Mapping ◽  
Wave Breaking ◽  
Breaking Strength ◽  
Vertical Wall ◽  
Breaking Waves ◽  
Long Waves ◽  
Amplitude Wave ◽  
One Dimensional ◽  
Wave Interference ◽  
Initial Wave

Recent modelling work has shown that abrupt bathymetric transitions can produce dramatic amplifications of long waves, under the influence of both nonlinearity and dispersion. Here, the evolution of wave packets towards a vertical wall over a varying bathymetry is investigated with a one-dimensional conformal-mapping spectral code. In this system, wave breaking, runup and reflection, wave interference and bathymetric effects are highlighted. Wave breaking is examined with respect to geometric, kinematic and energetic conditions, with consistent results. The breaking strength is characterized for spilling and plunging based on initial wave period and amplitude. Non-breaking waves are amplified by reflection, interference and the bathymetry leading to large runups. In a typical example inspired by a real-world bathymetry, the maximum runup amplification approaches a factor of 12 – large enough for a 3 m amplitude wave to overtop a 30 m cliff.

Measurement of Green Water on a 3D Structure

2009 ◽  
Author(s):  
Kusalika Ariyarathne ◽  
Kuang-An Chang ◽  
Richard Mercier
Keyword(s):  
Vertical Wall ◽  
3D Structure ◽  
Maximum Velocity ◽  
Breaking Waves ◽  
Velocity Fields ◽  
The Other ◽  
Green Water ◽  
Incoming Wave ◽  
Linear Distribution ◽  
The Waves

The present study investigates the velocity fields of plunging breaking waves impinging on a three-dimensional simplified ship-shape structure in a laboratory wave tank. Green water was generated as the waves break and overtop the structure. Bubble image velocimetry (BIV) was used to measure the velocity field of green water along the centerline of the deck. Two plunging wave conditions were tested and compared: one with waves impinging on the vertical wall of the structure at the initial still water level; the other with waves impacting on the horizontal deck surface. The velocity fields are quite different for the two cases even though the incoming wave heights and the wave periods are nearly identical. It was observed that the maximum horizontal velocity is higher for the case with waves compacting on the deck. The waves also passed the deck quicker than the other case. For both cases the profiles of the green water velocity shows a non-linear distribution with the maximum velocity occurring near the front of the water.

Numerical Simulation of Wave Overtopping Based on DualSPHysics

2013 ◽  
Vol 405-408 ◽  
pp. 1463-1471 ◽  
Author(s):  
Xing Ye Ni ◽  
Wei Bin Feng
Keyword(s):  
Numerical Simulation ◽  
Vertical Wall ◽  
Breaking Waves ◽  
Numerical Wave Tank ◽  
Regular Wave ◽  
Average Deviation ◽  
Wave Overtopping ◽  
Different Types ◽  
Numerical Wave ◽  
Run Up

To obtain a more detailed description of wave overtopping, a 2-D numerical wave tank is presented based on an open-source SPH platform named DualSPHysics, using a source generation and absorption technology suited for SPH methods with analytical relaxation approach. Numerical simulation of regular wave run-up and overtopping on typical sloping dikes is carried out and satisfactory agreements are shown between numerical results and experimental data. Another overtopping simulation of regular wave is conducted against six different types of seawalls (vertical wall, curved wall, recurved wall, 1:3 slope with smooth face, 1:1.5 slope with smooth face and 1:1.5 slope with stepped-face), which represents the details of various breaking waves interacting with different seawalls, and the average deviation of wave overtopping rate is 6.8%.

scholarly journals REDUCTION ON WAVE OVERTOPPING ON A SMOOTH DIKE BY MEANS OF A PARAPET

2011 ◽  
Vol 1 (32) ◽  
pp. 6 ◽  
Author(s):  
Koen Van Doorslaer ◽  
Julien De Rouck
Keyword(s):  
Vertical Wall ◽  
Breaking Waves ◽  
Wave Overtopping ◽  
Optimal Geometry ◽  
Efficient Construction ◽  
Major Reduction ◽  
Crest Height ◽  
Reduction Factors

A return wall or parapet is a very efficient construction built to reduce wave overtopping over sea structures. One of its main advantages is that this relative small construction can be built in a dike without increasing the crest height yet creating a major reduction in wave overtopping. In this paper only non-breaking waves attacking smooth dikes are investigated. A normal smooth dike, a smooth dike with vertical wall and a smooth dike with parapet have been tested. The results lead to reduction factors for a vertical wall or a parapet that can be introduced in the van der Meer formulas for wave overtopping over smooth dikes. The optimal geometry of the parapet has been subject of the research as well.

scholarly journals Experimental Evidence of the Influence of Recurves on Wave Loads at Vertical Seawalls

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 889 ◽  
Author(s):  
Dimitris Stagonas ◽  
Rajendran Ravindar ◽  
Venkatachalam Sriram ◽  
Stefan Schimmels
Keyword(s):  
Large Scale ◽  
Vertical Wall ◽  
Breaking Waves ◽  
Wave Loads ◽  
Incoming Wave ◽  
Wave Heights ◽  
The Mean ◽  
Peak Pressures ◽  
Wave Induced ◽  
Incident Waves

The role of recurves on top of seawalls in reducing overtopping has been previously shown but their influence in the distribution and magnitude of wave-induced pressures and forces on the seawall remains largely unexplored. This paper deals with the effects of different recurve geometries on the loads acting on the vertical wall. Three geometries with different arc lengths, or extremity angles (αe), were investigated in large-scale physical model tests with regular waves, resulting in a range of pulsating (non-breaking waves) to impulsive (breaking waves) conditions at the structure. As the waves hit the seawall, the up-rushing flow is deflected seawards by the recurve and eventually, re-enters the underlying water column and interacts with the next incoming wave. The re-entering water mass is, intuitively, expected to alter the incident waves but it was found that the recurve shape does not affect wave heights significantly. For purely pulsating conditions, the influence of αe on peak pressures and forces was also negligible. In marked contrast, the mean of the maximum impulsive pressure and force peaks increased, even by a factor of more than two, with the extremity angle. While there is no clear relation between the shape of the recurve and the mean peak pressures and forces, interestingly the mean of the 10% highest forces increases gradually with αe and this effect becomes more pronounced with increasing impact intensity.

scholarly journals Wave Overtopping of Stepped Revetments

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 1035 ◽  
Author(s):  
Nils B. Kerpen ◽  
Talia Schoonees ◽  
Torsten Schlurmann
Keyword(s):  
Scale Effects ◽  
Vertical Wall ◽  
Breaking Waves ◽  
Design Guidelines ◽  
Coastal Protection ◽  
Wave Overtopping ◽  
Wide Range ◽  
Run Up ◽  
The One ◽  
Parameter Ranges

Wave overtopping—i.e., excess of water over the crest of a coastal protection infrastructure due to wave run-up—of a smooth slope can be reduced by introducing slope roughness. A stepped revetment ideally constitutes a slope with uniform roughness and can reduce overtopping volumes of breaking waves up to 60% compared to a smooth slope. The effectiveness of the overtopping reduction decreases with increasing Iribarren number. However, to date a unique approach applicable for a wide range of boundary conditions is still missing. The present paper: (i) critically reviews and analyzes previous findings; (ii) contributes new results from extensive model tests addressing present knowledge gaps; and (iii) proposes a novel empirical formulation for robust prediction of wave overtopping of stepped revetments for breaking and non-breaking waves. The developed approach contrasts a critical assessment based on parameter ranges disclosed beforehand between a smooth slope on the one hand and a plain vertical wall on the other. The derived roughness reduction coefficient is developed and adjusted for a direct incorporation into the present design guidelines. Underlying uncertainties due to scatter of the results are addressed and quantified. Scale effects are highlighted.

Experimental Study of Scour Due to Breaking Waves in Front of Vertical-Wall Breakwaters

2004 ◽  
Author(s):  
Ali Hasanzadeh Daloui ◽  
Mirmosadegh Jamali
Keyword(s):  
Experimental Study ◽  
Empirical Equation ◽  
Vertical Wall ◽  
Breaking Waves ◽  
Scour Depth ◽  
Regular Waves ◽  
Factors Affecting ◽  
Wave Flume ◽  
Wave Heights

Scour is an important cause of instability of breakwaters. In case of vertical-wall breakwaters, toe scour can cause collapse of the whole structure. This paper is concerned with an experimental study of the effects of regular breaking waves on scour at toe of vertical-wall breakwaters. Experiments were carried out in a wave flume with regular waves for two cases of a beach with and without a breakwater. Bed profiles and scour depths for various wave heights, periods and depths were recorded. For the case of a beach without a breakwater, the observed bed profile types are compared to predictions. For the case of a beach with a breakwater, factors affecting the scour are investigated, and an empirical equation for scour depth at toe of a vertical wall is proposed.

scholarly journals 3D Particle Tracking Velocimetry applied to droplets generated by breaking waves

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Reyna Guadalupe RAMIREZ DE LA TORRE ◽  
Atle Jensen
Keyword(s):  
Particle Tracking ◽  
Wave Breaking ◽  
Particle Tracking Velocimetry ◽  
Wave Train ◽  
Vertical Wall ◽  
Breaking Waves ◽  
Initial Distribution ◽  
Polar Regions ◽  
Droplet Sizes ◽  
The Impact

One of the environmental difficulties of exploring the polar regions is marine icing. The understanding of this phenomenon is important for the safety of installations, ships and people that operates in these environments. One of the main sources of marine icing is wave breaking. Therefore, experimental and field work has been conducted to understand the break-up of waves in different situations and some explanation have been proposed to the instabilities that create the spray formation. In this work, two different situations of wave breaking were studied: 1. Solitary waves were created and steepened by the use of a beach. The waves impacted on a vertical wall with different wall heights. 2. Violent plunging breakers were created by a focusing wave train and a sloping beach. The main objective of these experiments was to quantify the production of droplets from the impact by using Particle Tracking Velocimetry in 3 dimensions. It was found that the initial distribution of droplet sizes is similar in both experiments. These distributions are compared with previous studies, where the distribution of droplet sizes in different experimental cases were approximated by lognormal, Weibull or G-distributions respectively.

scholarly journals EXPERIMENTAL RESULTS OF BREAKING WAVE IMPACT ON A VERTICAL WALL WITH AN OVERHANGING HORIZONTAL CANTILEVER SLAB

2011 ◽  
Vol 1 (32) ◽  
pp. 26
Author(s):  
Dogan Kisacik ◽  
Peter Troch ◽  
Philippe Van Bogaert
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
Vertical Wall ◽  
Breaking Waves ◽  
Wave Period ◽  
Breaking Wave ◽  
Wave Impact ◽  
Scaled Model ◽  
Physical Experiments ◽  
Horizontal Part

Physical experiments (at a scale of 1/20) are carried out using a vertical wall with horizontal cantilevering slab. Tests are conducted for a range of values of water depth, wave period and wave height. A parametric analysis of measured forces (Fh and Fv) both on the vertical and horizontal part of the scaled model respectively is conducted. The highest impact pressure and forces are measured in the case of breaking waves with a small air trap. Maximum pressures are measured around SWL and at the corner of the scaled model. The horizontal part of the scaled model is more exposed to impact waves than the vertical part. Fh and Fv are very sensitive for the variation of water depth (hs) and wave height (H) while variation of wave period (T) has a rather limited effect.

Bulk drag coefficient of a subaquatic vegetation subjected to irregular waves: Influence of Reynolds and Keulegan-Carpenter numbers

2020 ◽  
pp. 34-42
Author(s):  
Thibault Chastel ◽  
Kevin Botten ◽  
Nathalie Durand ◽  
Nicole Goutal
Keyword(s):  
Drag Coefficient ◽  
Wave Height ◽  
Wave Attenuation ◽  
Empirical Relationship ◽  
Breaking Waves ◽  
Irregular Waves ◽  
Geometrical Parameters ◽  
Flume Experiments ◽  
Seagrass Meadows ◽  
Artificial Vegetation

Seagrass meadows are essential for protection of coastal erosion by damping wave and stabilizing the seabed. Seagrass are considered as a source of water resistance which modifies strongly the wave dynamics. As a part of EDF R & D seagrass restoration project in the Berre lagoon, we quantify the wave attenuation due to artificial vegetation distributed in a flume. Experiments have been conducted at Saint-Venant Hydraulics Laboratory wave flume (Chatou, France). We measure the wave damping with 13 resistive waves gauges along a distance L = 22.5 m for the “low” density and L = 12.15 m for the “high” density of vegetation mimics. A JONSWAP spectrum is used for the generation of irregular waves with significant wave height Hs ranging from 0.10 to 0.23 m and peak period Tp ranging from 1 to 3 s. Artificial vegetation is a model of Posidonia oceanica seagrass species represented by slightly flexible polypropylene shoots with 8 artificial leaves of 0.28 and 0.16 m height. Different hydrodynamics conditions (Hs, Tp, water depth hw) and geometrical parameters (submergence ratio α, shoot density N) have been tested to see their influence on wave attenuation. For a high submergence ratio (typically 0.7), the wave attenuation can reach 67% of the incident wave height whereas for a low submergence ratio (< 0.2) the wave attenuation is negligible. From each experiment, a bulk drag coefficient has been extracted following the energy dissipation model for irregular non-breaking waves developed by Mendez and Losada (2004). This model, based on the assumption that the energy loss over the species meadow is essentially due to the drag force, takes into account both wave and vegetation parameter. Finally, we found an empirical relationship for Cd depending on 2 dimensionless parameters: the Reynolds and Keulegan-Carpenter numbers. These relationships are compared with other similar studies.

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