Journal of Marine Science and Engineering

Editorial

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3 pages, 167 KiB

Open AccessEditorial

Selected Papers from Coastlab18 Conference

by Javier L. Lara and Maria Maza

J. Mar. Sci. Eng. 2020, 8(4), 250; https://doi.org/10.3390/jmse8040250 - 03 Apr 2020

Viewed by 1338

Abstract

The 7th International Conference on The Application of Physical Modelling in Coastal and Port Engineering and Science, Coastlab18, was organized in Santander, Spain, from 22 to 26 May 2018, by the Instituto de Hidráulica Ambiental de la Universidad de Cantabria, IHCantabria [...] Full article

(This article belongs to the Special Issue Selected Papers from Coastlab18 Conference)

Research

Jump to: Editorial

18 pages, 6048 KiB

Open AccessArticle

Experimental and Numerical Analysis of the Hydrodynamics around a Vertical Cylinder in Waves

by Sara Corvaro, Andrea Crivellini, Francesco Marini, Andrea Cimarelli, Loris Capitanelli and Alessandro Mancinelli

J. Mar. Sci. Eng. 2019, 7(12), 453; https://doi.org/10.3390/jmse7120453 - 10 Dec 2019

Cited by 12 | Viewed by 2730

Abstract

The present study provides an extensive analysis on the hydrodynamics induced by a vertical slender pile under wave action. The authors carried out the study both experimentally and numerically, thus enabling a deep understanding of the flow physics. The experiments took place at [...] Read more.

The present study provides an extensive analysis on the hydrodynamics induced by a vertical slender pile under wave action. The authors carried out the study both experimentally and numerically, thus enabling a deep understanding of the flow physics. The experiments took place at a wave flume of the Università Politecnica delle Marche. Two different experimental campaigns were performed: In the former one, a mobile bed model was realized with the aims to study both the scour process and the hydrodynamics around the cylinder; in the latter one, the seabed was rigid in order to make undisturbed optical measurements, providing a deeper analysis of the hydrodynamics. The numerical investigation was made by performing a direct numerical simulation. A second order numerical discretization, both in time and in space, was used to solve the Navier–Stokes equations while a volume of fluid (VOF) approach was adopted for tracking the free surface. The comparison between experimental and numerical results is provided in terms of velocity, pressure distributions around the cylinder, and total force on it. The analysis of the pressure gradient was used to evaluate the generation and evolution of vortices around the cylinder. Finally, the relation between scour and bed shear stresses due to the structure of the vortex pattern around the pile was assessed. It is worth noting that the physical understanding of this last analysis was enabled by the combined use of experimental data on scour and numerical data on the flow pattern. Full article

(This article belongs to the Special Issue Selected Papers from Coastlab18 Conference)

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9 pages, 2071 KiB

Open AccessCommunication

Non-Hydrostatic Modeling of Waves Generated by Landslides with Different Mobility

by Ryan P. Mulligan, W. Andy Take and Gemma K. Bullard

J. Mar. Sci. Eng. 2019, 7(8), 266; https://doi.org/10.3390/jmse7080266 - 10 Aug 2019

Cited by 3 | Viewed by 4714

Abstract

Tsunamis are generated when landslides transfer momentum to water, and these waves are major hazards in the mountainous coastal areas of lakes, reservoir, and fjords. In this study, the influence of slide mobility on wave generation is investigated using new: (i) experimental observations; [...] Read more.

Tsunamis are generated when landslides transfer momentum to water, and these waves are major hazards in the mountainous coastal areas of lakes, reservoir, and fjords. In this study, the influence of slide mobility on wave generation is investigated using new: (i) experimental observations; (ii) theoretical relationships; and (iii) non-hydrostatic numerical predictions of the water surface and flow velocity evolution. This is accomplished by comparing landslides with low and high mobility and computing the momentum flux from landslides to water based on data collected in laboratory experiments. These slides have different materials, different impact velocities, different submarine runout distances, and generate very different waves. The waves evolve differently along the length of the waves’ flume, and the experimental results are in close agreement with high-resolution phase-resolving simulations. In this short communication, we describe new research on landslide generated waves conducted at Queen’s University, Canada, and presented at Coastlab18 in Santander, Spain. Full article

(This article belongs to the Special Issue Selected Papers from Coastlab18 Conference)

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16 pages, 4543 KiB

Open AccessArticle

Contribution of Infragravity Waves to Run-up and Overwash in the Pertuis Breton Embayment (France)

by Christopher H. Lashley, Xavier Bertin, Dano Roelvink and Gaël Arnaud

J. Mar. Sci. Eng. 2019, 7(7), 205; https://doi.org/10.3390/jmse7070205 - 02 Jul 2019

Cited by 17 | Viewed by 3349

Abstract

Wave run-up and dune overwash are typically assessed using empirical models developed for a specific range of often-simplistic conditions. Field experiments are essential in extending these formulae; yet obtaining comprehensive field data under extreme conditions is often challenging. Here, we use XBeach Surfbeat [...] Read more.

Wave run-up and dune overwash are typically assessed using empirical models developed for a specific range of often-simplistic conditions. Field experiments are essential in extending these formulae; yet obtaining comprehensive field data under extreme conditions is often challenging. Here, we use XBeach Surfbeat (XB-SB)—a shortwave-averaged but wave-group resolving numerical model—to complement a field campaign, with two main objectives: i) to assess the contribution of infragravity (IG) waves to washover development in a partially-sheltered area, with a highly complex bathymetry; and ii) to evaluate the unconventional nested-modeling approach that was applied. The analysis shows that gravity waves rapidly decrease across the embayment while IG waves are enhanced. Despite its exclusion of gravity-band swash, XB-SB is able to accurately reproduce both the large-scale hydrodynamics—wave heights and mean water levels across the 30 × 10 km embayment; and the local morphodynamics—steep post-storm dune profile and washover deposit. These findings show that the contribution of IG waves to dune overwash along the bay is significant and highlight the need for any method or model to consider IG waves when applied to similar environments. As many phase-averaged numerical models that are typically used for large-scale coastal applications exclude IG waves, XB-SB may prove to be a suitable alternative. Full article

(This article belongs to the Special Issue Selected Papers from Coastlab18 Conference)

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12 pages, 3229 KiB

Open AccessArticle

Experimental Study on Toe Scouring at Sloping Walls with Gravel Foreshores

by M. Salauddin and J. M. Pearson

J. Mar. Sci. Eng. 2019, 7(7), 198; https://doi.org/10.3390/jmse7070198 - 27 Jun 2019

Cited by 13 | Viewed by 3729

Abstract

Sea defences, such as urban seawalls can fail due to the development of a scour hole at the toe of the structure. The scour depth or the information on ground levels at the structure toe is required for the sustainable management of coastal [...] Read more.

Sea defences, such as urban seawalls can fail due to the development of a scour hole at the toe of the structure. The scour depth or the information on ground levels at the structure toe is required for the sustainable management of coastal defences, due to its influence on the structural performance. This research reports and summarises the main findings of a new laboratory study on toe scouring at a smooth sloping wall with permeable gravel foreshore. A set of small-scale laboratory experiments of wave-induced scouring at sloping seawalls were conducted. Two gravel sediments of prototype d₅₀ values of 13 mm and 24 mm were used to simulate the permeable 1:20 (V:H) gravel beach configurations in the front of a smooth 1 in 2 sloping wall. Each experiment comprised of a sequence of around 1000 random waves of a JONSWAP energy spectrum with a peak enhancement factor of 3.3. The relationship of the scour depth with toe water depth, Iribarren number, and wall slope were investigated from the test results of this work and through a comparison with available datasets in the literature. The results of this study showed that the relative toe water depth and Iribarren number influence the relative toe scour depth at a sloping structure on a shingle beach. Within the experimental limitations, the maximum toe scour depths were observed for the experiments under spilling and plunging wave attack. Full article

(This article belongs to the Special Issue Selected Papers from Coastlab18 Conference)

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15 pages, 3266 KiB

Open AccessArticle

Physical Modelling of Blue Mussel Dropper Lines for the Development of Surrogates and Hydrodynamic Coefficients

by Jannis Landmann, Thorsten Ongsiek, Nils Goseberg, Kevin Heasman, Bela H. Buck, Jens-André Paffenholz and Arndt Hildebrandt

J. Mar. Sci. Eng. 2019, 7(3), 65; https://doi.org/10.3390/jmse7030065 - 12 Mar 2019

Cited by 16 | Viewed by 3652

Abstract

In this work, laboratory tests with live bivalves as well as the conceptual design of additively manufactured surrogate models are presented. The overall task of this work is to develop a surrogate best fitting to the live mussels tested in accordance to the [...] Read more.

In this work, laboratory tests with live bivalves as well as the conceptual design of additively manufactured surrogate models are presented. The overall task of this work is to develop a surrogate best fitting to the live mussels tested in accordance to the identified surface descriptor, i.e., the Abbott–Firestone Curve, and to the hydrodynamic behaviour by means of drag and inertia coefficients. To date, very few investigations have focused on loads from currents as well as waves. Therefore, tests with a towing carriage were carried out in a wave flume. A custom-made rack using mounting clamps was built to facilitate carriage-run tests with minimal delays. Blue mussels (Mytilus edulis) extracted from a site in Germany, which were kept in aerated seawater to ensure their survival for the test duration, were used. A set of preliminary results showed drag and inertia coefficients

C_{D}

and

C_{M}

ranging from 1.16–3.03 and 0.25 to 1.25. To derive geometrical models of the mussel dropper lines, 3-D point clouds were prepared by means of 3-D laser scanning to obtain a realistic surface model. Centered on the 3-D point cloud, a suitable descriptor for the mass distribution over the surface was identified and three 3-D printed surrogates of the blue mussel were developed for further testing. These were evaluated regarding their fit to the original 3-D point cloud of the live blue mussels via the chosen surface descriptor. Full article

(This article belongs to the Special Issue Selected Papers from Coastlab18 Conference)

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15 pages, 4398 KiB

Open AccessArticle

Statistical Analysis of the Stability of Rock Slopes

by Marcel R.A. van Gent, Ermano de Almeida and Bas Hofland

J. Mar. Sci. Eng. 2019, 7(3), 60; https://doi.org/10.3390/jmse7030060 - 06 Mar 2019

Cited by 11 | Viewed by 2763

Abstract

Physical model tests were performed in a wave flume at Deltares with rock armoured slopes. A shallow foreshore was present. At deep water, the same wave conditions were used, but by applying different water levels, the wave loading on the rock armoured slopes [...] Read more.

Physical model tests were performed in a wave flume at Deltares with rock armoured slopes. A shallow foreshore was present. At deep water, the same wave conditions were used, but by applying different water levels, the wave loading on the rock armoured slopes increased considerably with increasing water levels. This allowed an assessment of the effects of sea level rise. Damage was measured by using digital stereo photography (DSP), which provides information on each individual stone that is displaced. Two test series were performed five times. This allowed for a statistical analysis of the damage to rock armoured slopes, which is uncommon due to the absence of statistical information based on a systematic repetition of test series. The statistical analysis demonstrates the need for taking the mean damage into account in the design of rock armoured slopes. This is important in addition to characterising the damage itself by erosion areas and erosion depths. The relation between damage parameters, such as the erosion area and erosion depth, was obtained from the tests. Besides tests with a straight slope, tests with a berm in the seaward slopes were also performed. A new method to take the so-called length effect into account is proposed to extrapolate results from physical model tests to real structures. This length effect is important, but is normally overlooked in the design of rubble mound structures. Standard deviations based on the presented model tests were used. Full article

(This article belongs to the Special Issue Selected Papers from Coastlab18 Conference)

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12 pages, 2239 KiB

Open AccessArticle

Separation of Long-Crested Nonlinear Bichromatic Waves into Incident and Reflected Components

by Thomas Lykke Andersen, Mads R. Eldrup and Maria Clavero

J. Mar. Sci. Eng. 2019, 7(2), 39; https://doi.org/10.3390/jmse7020039 - 07 Feb 2019

Cited by 6 | Viewed by 2547

Abstract

Methods for the separation of long-crested linear waves into incident and reflected waves have existed for more than 40 years. The present paper presents a new method for the separation of nonlinear bichromatic long-crested waves into incident and reflected components, as well as [...] Read more.

Methods for the separation of long-crested linear waves into incident and reflected waves have existed for more than 40 years. The present paper presents a new method for the separation of nonlinear bichromatic long-crested waves into incident and reflected components, as well as into free and bound components. The new method is an extension of a recently proposed method for the separation of nonlinear regular waves. The new methods include both bound and free higher harmonics, which is important for nonlinear waves. The applied separation method covers interactions to the third order, but can easily be extended to a higher orders. Synthetic tests, as well as physical model tests, showed that the method accurately predict the bound amplitudes and incident and reflected surface elevations of nonlinear bichromatic waves. The new method is important in order to be able to describe the detailed characteristics of nonlinear bichromatic waves and their reflection. Full article

(This article belongs to the Special Issue Selected Papers from Coastlab18 Conference)

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17 pages, 3039 KiB

Open AccessArticle

An Operational Wave System within the Monitoring Program of a Mediterranean Beach

by Andrea Ruju, Marinella Passarella, Daniele Trogu, Carla Buosi, Angelo Ibba and Sandro De Muro

J. Mar. Sci. Eng. 2019, 7(2), 32; https://doi.org/10.3390/jmse7020032 - 02 Feb 2019

Cited by 11 | Viewed by 3748

Abstract

This work assesses the performance of an operational wave system in the Mediterranean Sea by comparing computed data with measurements collected at different water depths. Nearshore data measurements were collected through a field experiment carried out at Poetto beach (Southern Sardinia, Italy) during [...] Read more.

This work assesses the performance of an operational wave system in the Mediterranean Sea by comparing computed data with measurements collected at different water depths. Nearshore data measurements were collected through a field experiment carried out at Poetto beach (Southern Sardinia, Italy) during spring 2017. In addition to coastal observations, we use intermediate and deep water wave data measured by two buoys: one situated North-West of Corsica and the other in the Gulf of Lion. The operational wave system runs once a day to predict the wave evolution up to five days in advance. We use a multi-grid approach in which a large grid extends over the entire Mediterranean basin and a fine grid covers the coastal seas surrounding the islands of Sardinia and Corsica. The comparison with measurements shows that the operational wave system is able to satisfactorily reproduce the wave evolution in deep and intermediate waters where the relative error of the significant wave height is 17%. The error exceeding 25% in coastal waters suggests that the use of a finer grid and the coupling with an atmospheric model able to catch local effects is advisable to accurately address nearshore wave processes driven by coastal wind forcing. Full article

(This article belongs to the Special Issue Selected Papers from Coastlab18 Conference)

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12 pages, 5005 KiB

Open AccessArticle

Interaction of Swell and Sea Waves with Partially Reflective Structures for Possible Engineering Applications

by Andrea Lira-Loarca, Asunción Baquerizo and Sandro Longo

J. Mar. Sci. Eng. 2019, 7(2), 31; https://doi.org/10.3390/jmse7020031 - 02 Feb 2019

Cited by 4 | Viewed by 2804

Abstract

In this work, we investigate the interaction between the combination of wind-driven and regular waves and a chamber defined by a rigid wall and a thin vertical semi-submerged barrier. A series of laboratory experiments were performed with different values of incident wave height, [...] Read more.

In this work, we investigate the interaction between the combination of wind-driven and regular waves and a chamber defined by a rigid wall and a thin vertical semi-submerged barrier. A series of laboratory experiments were performed with different values of incident wave height, wave period, and wind speed. The analysis focuses on the effect of the geometry of the system characterized in terms of its relative submergence d/h and relative width B/L. Results show that for the case of d/h = 0.58 a resonant effect takes place inside the chamber regardless of the wind speed. Wind-driven waves have a higher influence on the variation of the wave period of the waves seaward and leeward of the plate, as well as on the phase lag. Results show that the amplification or reduction of the wave energy inside the chamber is closely related to the wave period as compared to the 1st order natural period of the chamber. Full article

(This article belongs to the Special Issue Selected Papers from Coastlab18 Conference)

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10 pages, 1786 KiB

Open AccessArticle

Development of an Outdoor Wave Basin to Conduct Long-Term Model Tests with Real Vegetation for Green Coastal Infrastructures

by Jochen Michalzik, Sven Liebisch and Torsten Schlurmann

J. Mar. Sci. Eng. 2019, 7(1), 18; https://doi.org/10.3390/jmse7010018 - 18 Jan 2019

Cited by 3 | Viewed by 3156

Abstract

The demand for physical model tests with real vegetation is increasing due to the current trend to elucidate the performance and durability of green coastal infrastructures to ensure and promote ecosystem services. To address this demand, a new outdoor wave basin (OWB) was [...] Read more.

The demand for physical model tests with real vegetation is increasing due to the current trend to elucidate the performance and durability of green coastal infrastructures to ensure and promote ecosystem services. To address this demand, a new outdoor wave basin (OWB) was built in August 2017 at the Ludwig-Franzius-Institute in Hannover, Germany. This paper reviews the general characteristics and the ongoing development of the new OWB. First insights into the long-term development of the ecosystem services of different grass revetments are discussed in terms of their ecological value and safety standards of sea dikes. Focus is placed on the resistance and ecological value of different grass mixtures that are typically applied on sea dikes situated along the North Sea. Further research concepts are briefly described to highlight how experiments in the new OWB may contribute to the current understanding and design recommendations of green coastal infrastructures. The operation of the OWB enables the performance of long-term experiments over seasonal growth stages of coastal vegetation using either fresh or seawater with wave load stresses and varying sea water levels. The first conducted experiments with different grass revetment combinations mimic typical storm surge conditions with a constant wave load (with a duration of up to 10 hours every second week) on a natural dike. Full article

(This article belongs to the Special Issue Selected Papers from Coastlab18 Conference)

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15 pages, 4429 KiB

Open AccessArticle

Applicability of Nonlinear Wavemaker Theory

by Mads Røge Eldrup and Thomas Lykke Andersen

J. Mar. Sci. Eng. 2019, 7(1), 14; https://doi.org/10.3390/jmse7010014 - 14 Jan 2019

Cited by 19 | Viewed by 4668

Abstract

Generation of high-quality waves is essential when making numerical or physically model tests. When using a wavemaker theory outside the validity area, spurious waves are generated. In order to investigate the validity of different wave generation methods, new model test results are presented [...] Read more.

Generation of high-quality waves is essential when making numerical or physically model tests. When using a wavemaker theory outside the validity area, spurious waves are generated. In order to investigate the validity of different wave generation methods, new model test results are presented where linear and nonlinear wave generation theories are tested on regular and irregular waves. A simple modification to the second-order wavemaker theory is presented, which significantly reduces the generation of spurious waves when used outside its range of applicability. For highly nonlinear regular waves, only the ad-hoc unified wave generation based on stream function wave theory was found acceptable. For irregular waves, similar conclusions are drawn, but the modified second-order wavemaker method is more relevant. This is because the ad-hoc unified generation method for irregular waves requires the wave kinematics to be calculated by a numerical model, which might be quite time-consuming. Finally, a table is presented with the range of applicability for each wavemaker method for regular and irregular waves. Full article

(This article belongs to the Special Issue Selected Papers from Coastlab18 Conference)

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15 pages, 4745 KiB

Open AccessArticle

Damage Characterization of Rock Slopes

by Ermano de Almeida, Marcel R. A. van Gent and Bas Hofland

J. Mar. Sci. Eng. 2019, 7(1), 10; https://doi.org/10.3390/jmse7010010 - 09 Jan 2019

Cited by 12 | Viewed by 3000

Abstract

In order to design reliable coastal structures, for present and future scenarios, universal and precise damage assessment methods are required. This study addresses this need, and presents improved damage characterization methods for coastal structures with rock armored slopes. The data used in this [...] Read more.

In order to design reliable coastal structures, for present and future scenarios, universal and precise damage assessment methods are required. This study addresses this need, and presents improved damage characterization methods for coastal structures with rock armored slopes. The data used in this study were obtained from a test campaign carried out at Deltares within the European Union (EU) Hydralab+ framework. During these tests, advanced measuring techniques (digital stereo photography) were used, which are able to survey the full extension of the structure and identify local variations of damage. The damage characterization method proposed here is based on three fundamental aspects: clear damage concepts, precise damage parameters, and high resolution measuring techniques. Regarding damage concepts, first, the importance of the characterization width is studied. For damage parameters obtained from the maximum erosion depth observed in a given width (E_3D,m), the measured damage increases continuously with increased characterization width. However, for damage parameters obtained from width-averaged profiles (S and E_2D), the measured damage reduces with increased characterization width. Second, a new definition of damage limits (damage initiation, intermediate damage, and failure) is presented and calibrated. Regarding the damage parameters, the parameter E_3D,5, which describes the maximum erosion depth within the characterization width, is recommended as a robust damage parameter for conventional and non-conventional configurations based on four main characteristics: its low bias, its low random error, the ability to distinguish damage levels, and its validity and suitability for all types of structures (conventional and non-conventional). In addition, the results from this study show that the damage measured with the damage parameter E_3D,5 presents an extreme value distribution. Full article

(This article belongs to the Special Issue Selected Papers from Coastlab18 Conference)

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17 pages, 4273 KiB

Open AccessArticle

Wave Impact Pressures on Stepped Revetments

by Nils B. Kerpen, Talia Schoonees and Torsten Schlurmann

J. Mar. Sci. Eng. 2018, 6(4), 156; https://doi.org/10.3390/jmse6040156 - 13 Dec 2018

Cited by 5 | Viewed by 3320

Abstract

The wave impacts on horizontal and vertical step fronts of stepped revetments is investigated by means of hydraulic model tests conducted with wave spectra in a wave flume. Wave impacts on revetments with relative step heights of 0.3 < H_m₀/ [...] Read more.

The wave impacts on horizontal and vertical step fronts of stepped revetments is investigated by means of hydraulic model tests conducted with wave spectra in a wave flume. Wave impacts on revetments with relative step heights of 0.3 < H_m₀/S_h < 3.5 and a constant slope of 1:2 are analyzed with respect to (1) the probability distribution of the impacts, (2) the time evolution of impacts including a classification of load cases, and (3) a special distribution of the position of the maximum impact. The validity of the approved log-normal probability distribution for the largest wave impacts is experimentally verified for stepped revetments. The wave impact properties for stepped revetments are compared with those of vertical seawalls, showing that their impact rising times are within the same range. The impact duration for stepped revetments is shorter and decreases with increasing step height. Maximum horizontal wave impact loads are about two times larger than the corresponding maximum vertical wave impact loads. Horizontal and vertical impact loads increase with a decreasing step height. Data are compared with findings from literature for stepped revetments and vertical walls. A prediction formula is provided to calculate the maximum horizontal wave impact at stepped revetments along its vertical axis. Full article

(This article belongs to the Special Issue Selected Papers from Coastlab18 Conference)

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11 pages, 1957 KiB

Open AccessArticle

Cubipod^® Armor Design in Depth-Limited Regular Wave-Breaking Conditions

by M. Esther Gómez-Martín, María P. Herrera, Jose A. Gonzalez-Escriva and Josep R. Medina

J. Mar. Sci. Eng. 2018, 6(4), 150; https://doi.org/10.3390/jmse6040150 - 06 Dec 2018

Cited by 6 | Viewed by 2793

Abstract

Armor stability formulas for mound breakwaters are commonly based on 2D small-scale physical tests conducted in non-overtopping and non-breaking conditions. However, most of the breakwaters built around the world are located in breaking or partially-breaking wave conditions, where they must withstand design storms [...] Read more.

Armor stability formulas for mound breakwaters are commonly based on 2D small-scale physical tests conducted in non-overtopping and non-breaking conditions. However, most of the breakwaters built around the world are located in breaking or partially-breaking wave conditions, where they must withstand design storms having some percentage of large waves breaking before they reach the structure. In these cases, the design formulas for non-breaking wave conditions are not fully valid. This paper describes the specific 2D physical model tests carried out to analyze the trunk hydraulic stability of single- and double-layer Cubipod^® armors in depth-limited regular wave breaking and non-overtopping conditions with horizontal foreshore (m = 0) and armor slope (α) with cotα = 1.5. An experimental methodology was established to ensure that 100 waves attacked the armor layer with the most damaging combination of wave height (H) and wave period (T) for the given water depth (h_s). Finally, for a given water depth, empirical formulas were obtained to estimate the Cubipod^® size which made the armor stable regardless of the deep-water wave storm. Full article

(This article belongs to the Special Issue Selected Papers from Coastlab18 Conference)

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13 pages, 7345 KiB

Open AccessArticle

Wave Overtopping over Coastal Structures with Oblique Wind and Swell Waves

by Ivo M. Van der Werf and Marcel R.A. Van Gent

J. Mar. Sci. Eng. 2018, 6(4), 149; https://doi.org/10.3390/jmse6040149 - 06 Dec 2018

Cited by 15 | Viewed by 3536

Abstract

Most guidelines on wave overtopping over coastal structures are based on conditions with waves from one direction only. Here, wave basin tests with oblique wave attack are presented where waves from one direction are combined with waves from another direction. This is especially [...] Read more.

Most guidelines on wave overtopping over coastal structures are based on conditions with waves from one direction only. Here, wave basin tests with oblique wave attack are presented where waves from one direction are combined with waves from another direction. This is especially important for locations where wind waves approach a coastal structure under a specific direction while swell waves approach the coastal structure under another direction. The tested structure was a dike with a smooth and impermeable 1:4 slope. The test programme consisted of four types of wave loading: (1) Wind waves only: “sea” (approaching the structure with an angle of 45°), (2) Wind waves and swell waves from the same direction (45°), (3) Wind waves and swell waves, simultaneously from two different directions (45° and −45°, thus perpendicular to each other), and (4) Wind waves, simultaneously from two different directions (45° and −45°, thus perpendicular to each other). Existing guidelines on wave overtopping have been extended to predict wave overtopping discharges under the mentioned types of wave loading (oblique sea and swell conditions). Full article

(This article belongs to the Special Issue Selected Papers from Coastlab18 Conference)

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13 pages, 4827 KiB

Open AccessArticle

Hydraulic Stability of the Armor Layer of Overtopped Breakwaters

by Gloria Argente, M. Esther Gómez-Martín and Josep R. Medina

J. Mar. Sci. Eng. 2018, 6(4), 143; https://doi.org/10.3390/jmse6040143 - 27 Nov 2018

Cited by 15 | Viewed by 4632

Abstract

Mound breakwaters with significant overtopping rates in depth-limited conditions are common in practice due to social concern about the visual impact of coastal structures and sea level rise due to climatic change. For overtopped mound breakwaters, the highest waves pass over the crest [...] Read more.

Mound breakwaters with significant overtopping rates in depth-limited conditions are common in practice due to social concern about the visual impact of coastal structures and sea level rise due to climatic change. For overtopped mound breakwaters, the highest waves pass over the crest producing armor damage, not only to the front slope, but also to the crest and the rear slope. To guarantee the breakwater stability, it is necessary to limit the armor damage in the three parts of the structure: Front slope, crest, and rear slope. This paper describes the hydraulic stability of the armor layer of medium and low-crested structures in wave breaking conditions. Small-scale physical model tests were carried out with different relative crest freeboards and three armor units: Rocks, cubes, and Cubipods. The armor damage progression in the front slope, crest, and rear slope was analyzed using the Virtual Net method to consider the heterogeneous packing and porosity evolution along the armor slope. A comparison is provided between the hydraulic stability of the different armors and their relationship with the measured overtopping volumes. Full article

(This article belongs to the Special Issue Selected Papers from Coastlab18 Conference)

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