A LABORATORY STUDY ON WAVE OVERTOPPING AT VERTICAL SEAWALLS WITH A SHINGLE FORESHORE

Coastal Engineering Proceedings ◽

10.9753/icce.v36.waves.56 ◽

2018 ◽

pp. 56 ◽

Cited By ~ 1

Author(s):

Md Salauddin ◽

Jonathan Pearson

Keyword(s):

Laboratory Study ◽

Vertical Wall ◽

Empirical Equations ◽

Laboratory Measurements ◽

Coastal Structures ◽

Wave Overtopping ◽

Empirical Prediction ◽

Discharge Rates ◽

Vertical Walls

The existing empirical prediction formulae to determine the wave overtopping characteristics are mainly based on the laboratory measurements with the use of an impermeable foreshore slope in front of the structure. Recently, EurOtop (2016), an updated version of previous overtopping manual has been published with revised empirical equations to estimate mean overtopping discharge rates at plain vertical walls with and without foreshore.As past studies were mostly carried out at vertical seawalls on a fixed impermeable bed, little knowledge is available on the performance of these processes at coastal structures on a permeable shingle beach. This study presents the baseline overtopping characteristics at a plain vertical wall on an impermeable 1:20 foreshore slope, and compares the results with existing empirical predictions (EurOtop, 2016). In this paper, only the results on mean overtopping discharge and mean sediment rate at vertical walls are reported.

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VERTICAL SEA WALL CREST MODIFICATIONS FOR OVERTOPPING

Coastal Engineering Proceedings ◽

10.9753/icce.v36.structures.71 ◽

2018 ◽

pp. 71

Author(s):

Dogan Kisacik ◽

Gulizar Ozyurt Tarakcioglu ◽

Cuneyt Baykal ◽

Gokhan Kaboglu

Keyword(s):

Urban Areas ◽

Vertical Wall ◽

Breaking Wave ◽

Limited Information ◽

Coastal Structures ◽

Wave Overtopping ◽

Wave Basin ◽

First Results ◽

Set Up ◽

Sea Wall

Crest modifications such as a storm wall, parapet or a bullnose are widely used to reduce the wave overtopping over coastal structures where spatial and visual demands restrict the crest heights, especially in urban areas. Although reduction factors of these modifications have been studied for sloped structures in EurOtop Manual (2016), there is limited information regarding the vertical structures. This paper presents the experimental set-up and first results of wave overtopping tests for a vertical wall with several different super structure types: a) seaward storm wall, b) sloping promenade, c) landward storm wall, d) stilling wave basin (SWB), e) seaward storm wall with parapet, f) landward storm wall on the horizontal promenade with parapet, g) landward storm wall with parapet, h) stilling wave basin (SWB) with parapet, under breaking wave conditions. The SWB is made up of a seaward storm wall (may be a double shifted rows) , a sloping promenade (basin) and a landward storm wall. The seaward storm wall is partially permeable to allow the evacuation of the water in the basin.

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EXPECTED DISCHARGE OP IRREGULAR WAVE OVERTOPPING

Coastal Engineering Proceedings ◽

10.9753/icce.v11.54 ◽

1968 ◽

Vol 1 (11) ◽

pp. 54 ◽

Cited By ~ 4

Author(s):

Senri Tsuruta ◽

Yoshimi Goda

Keyword(s):

Vertical Wall ◽

Laboratory Data ◽

Irregular Waves ◽

Linear Summation ◽

Wave Overtopping ◽

Irregular Wave ◽

Concrete Blocks ◽

Vertical Walls ◽

Expected Values ◽

Sea Wall

An experiment was carried out on the overtopping of mechanically generated irregular waves over vertical walls. The experimental discharge was almost in agreement with the expected discharge which had been calculated with the wave height histogram and the data of regular wave overtopping based on the principle of linear summation. The expected values of overtopping discharge were calculated for various laboratory data, which had been represented in a unified form of non-dimensional quantities. The calculation has yielded two diagrams of expected overtopping discharge, one for the sea wall of vertical wall type and the othei for the sea wall covered with artificial concrete blocks.

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THE COMPARISON OF EMPIRICAL FORMULAE FOR THE PREDICTION OF MEAN WAVE OVERTOPPING RATE AT ARMORED SLOPED STRUCTURES

Coastal Engineering Proceedings ◽

10.9753/icce.v36v.structures.22 ◽

2020 ◽

pp. 22

Author(s):

Ali Koosheh ◽

Amir Etemad-Shahidi ◽

Nick Cartwright ◽

Rodger Tomlinson ◽

Shabnam Hosseinzadeh

Keyword(s):

Detailed Comparison ◽

Accurate Estimation ◽

Hydraulic Parameters ◽

Test Results ◽

Laboratory Measurements ◽

Coastal Structures ◽

Structural Geometry ◽

Wave Overtopping ◽

Wave Characteristics ◽

Potential Impact

Armored sloped structures are generally used to provide the safety of their lee side, i. e. harbours and coastal regions against wave attacks and storm surge. Recently, due to the potential impact of climate change, increasing emphasis has been placed on their hydraulic performance (e.g. Pillai et al. 2019). Thus, accurate estimation of wave overtopping rate, as the hydraulic response of coastal structures, has an important role in design. Wave overtopping is a complex phenomenon and depends on structural geometry and wave characteristics. Hence, empirical formulae are generally used for estimation of mean overtopping rate. These formulae have been derived from laboratory measurements in which the dimensionless measured overtopping rates are correlated with the dimensionless structural and hydraulic parameters through physical arguments. The most well-known formulae for wave overtopping prediction can be found in the Coastal Engineering Manual (2012) and European Overtopping Manual (EurOtop, 2018). The CLASH database as one of the most comprehensive datasets, was initially provided by De Rouck and Geeraerts (2005). This data base was recently updated by including more test results (EurOtop, 2018). However, a detailed comparison of formulae proposed for the estimation of overtopping rates at rubble mound sloped structures is not reported. The present paper aims to evaluate the performance of existing empirical formulae namely EurOtop 2018 (hereafter ET18), Owen (1982), van der Meer and Janssen (1995) (hereafter VMJ) and Jafari and Etemad-Shahidi (2012) (hereafter JES) against EurOtop database (updated CLASH database). The analysis includes structures with different armor types (rock, concrete cubes etc.) with both impermeable and permeable cores, to evaluate the capability of used formulae under different conditions.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/0TL5zFCf6GU

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WAVE OVERTOPPING AT DYKES WITH TOPPED VERTICAL WALL - IMPACTS OF OBLIQUE WAVE ATTACK

Coastal Engineering Proceedings ◽

10.9753/icce.v33.structures.60 ◽

2012 ◽

Vol 1 (33) ◽

pp. 60

Author(s):

Nils B. Kerpen ◽

Torsten Schlurmann

Keyword(s):

Numerical Models ◽

Vertical Wall ◽

Coastal Protection ◽

Wave Spectra ◽

Wave Overtopping ◽

Oblique Wave ◽

Wave Basin ◽

Vertical Walls ◽

The Mean ◽

Analytical Approaches

Hydraulic model tests at a scale of 1:10 are carried out in a 40 m x 25 m wave basin with a state-of-the-art 3D wave generator in order to collect wave overtopping data at vertical walls and dykes with topped vertical walls. Wave conditions in the near field of the structures, velocities under waves and the mean overtopping discharge are measured. The experiments have been commissioned by the Lower Saxony Water Management, Coastal Defense and Nature Conservation Agency (NLWKN) with the purpose to deliver essential overtopping data for validation of numerical models. Two main geometries are analyzed – each for two specific wave spectra. Overtopping rates are investigated with respect to the remaining freeboard height Rc and the influence of oblique wave attack β{0°, 10°, 30°, 40°, 50°, 60°}. Results are compared with existing analytical approaches. As expected for this special geometrical coastal protection structure, it is examined that overtopping discharges increase with decreasing remaining freeboard. Intensity of the reduction is more dependent on the wave spectra than on the dyke geometry. Mean wave overtopping rate increases with decreasing relative water depth Hm0/d directly in front of the vertical wall. Furthermore, the mean wave overtopping rates decrease with an increasing angle of wave attack β. The correlation between mean wave overtopping rate and freeboard height is given in four newly adapted design formulas, describing the overtopping performance of the two discussed dyke geometries with topped vertical walls.

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Slit-type Breakwater; Box-type Wave Absorber

Coastal Engineering Proceedings ◽

10.9753/icce.v15.154 ◽

1976 ◽

Vol 1 (15) ◽

pp. 154 ◽

Cited By ~ 2

Author(s):

Shoshichiro Nagai ◽

Shohachi Kakuno

Keyword(s):

Cross Section ◽

Water Depth ◽

Vertical Wall ◽

Bottom Wall ◽

Front Wall ◽

Type Wave ◽

Composite Type ◽

New Type ◽

Vertical Walls ◽

Horizontal Bottom

A box-type wave absorber, which is composed of a perforated vertical front-wall and a perforated, horizontal bottom-wall, has been proved by a number of experiments to show lower coefficients of reflection and more distinguished reduction of wave pressures than the perforated vertical- wall breakwater. A breakwater of composite-type, which is 1500 m long and to be built at a water depth of 10 to 11 m below the Datum Line in the Port of Osaka, is being designed to set this new type of wave absorber in the concrete caissons of the vertical-walls which is named "a slit-type breakwater". The typical cross-section of the breakwater and the advantages of the slit-type breakwater are presented herein.

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APPLICATION OF SMOOTHED PARTICLE HYDRODYNAMICS IN EVALUATING THE PERFORMANCE OF COASTAL RETROFIT STRUCTURES

Coastal Engineering Proceedings ◽

10.9753/icce.v36.papers.109 ◽

2018 ◽

pp. 109 ◽

Cited By ~ 4

Author(s):

Soroush Abolfathi ◽

Dong Shudi ◽

Sina Borzooei ◽

Abbas Yeganeh-Bakhtiari ◽

Jonathan Pearson

Keyword(s):

Numerical Model ◽

Smoothed Particle Hydrodynamics ◽

Vertical Wall ◽

Laboratory Data ◽

Wave Structure ◽

Base Case ◽

Submerged Breakwater ◽

Wave Overtopping ◽

Particle Hydrodynamics ◽

Smoothed Particle

This study develops an accurate numerical tool for investigating optimal retrofit configurations in order to minimize wave overtopping from a vertical seawall due to extreme climatic events and under changing climate. A weakly compressible smoothed particle hydrodynamics (WCSPH) model is developed to simulate the wave-structure interactions for coastal retrofit structures in front of a vertical seawall. A range of possible physical configurations of coastal retrofits including re-curve wall and submerged breakwater are modelled with the numerical model to understand their performance under different wave and structural conditions. The numerical model is successfully validated against laboratory data collected in 2D wave flume at Warwick Water Laboratory. The findings of numerical modelling are in good agreement with the laboratory data. The results indicate that recurve wall is more effective in mitigating wave overtopping and provides more resilience to coastal flooding in comparison to base-case (plain vertical wall) and submerged breakwater retrofit.

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IRREGULAR WAVE OVERTOPPING RATES

Coastal Engineering Proceedings ◽

10.9753/icce.v19.22 ◽

1984 ◽

Vol 1 (19) ◽

pp. 22 ◽

Cited By ~ 2

Author(s):

Scott L. Douglass

Keyword(s):

Shallow Water ◽

Shore Protection ◽

Coastal Structures ◽

Wave Overtopping ◽

Manual Method ◽

Irregular Wave ◽

Order Of Magnitude

Methods for estimating wave overtopping of coastal structures are reviewed and compared with the very limited available data and with each other. The different methods yield results which can vary more than an order-of-magnitude. For vertical seawalls, the U. S. Army Engineer Shore Protection Manual method estimates more overtopping than Goda's method except in very shallow water. For sloped structures, the Shore Protection Manual method usually estimates less overtopping than Battjes' method and Owen's method. However, data for adequately evaluating how well these methods predict overtopping has not been published.

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The Effect of the Top Wall Temperature on the Laminar Natural Convection in Rectangular Cavities With Different Aspect Ratios

Journal of Heat Transfer ◽

10.1115/1.2993138 ◽

2009 ◽

Vol 131 (5) ◽

Cited By ~ 9

Author(s):

Wenjiang Wu ◽

Chan Y. Ching

Keyword(s):

Natural Convection ◽

Aspect Ratio ◽

Wall Temperature ◽

Vertical Wall ◽

Flow Region ◽

Temperature Profiles ◽

Aspect Ratios ◽

Vertical Walls ◽

C And N ◽

Laminar Natural Convection

The effect of the top wall temperature on the laminar natural convection in air-filled rectangular cavities driven by a temperature difference across the vertical walls was investigated for three different aspect ratios of 0.5, 1.0, and 2.0. The temperature distributions along the heated vertical wall were measured, and the flow patterns in the cavities were visualized. The experiments were performed for a global Grashof number of approximately 1.8×108 and nondimensional top wall temperatures from 0.52 (insulated) to 1.42. As the top wall was heated, the flow separated from the top wall with an undulating flow region in the corner of the cavity, which resulted in a nonuniformity in the temperature profiles in this region. The location and extent of the undulation in the flow are primarily determined by the top wall temperature and nearly independent of the aspect ratio of the cavity. The local Nusselt number was correlated with the local Rayleigh number for all three cavities in the form of Nu=C⋅Ran, but the values of the constants C and n changed with the aspect ratio.

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