Derivation of Wave Overtopping Formulas for Vertical Walls Using GMDH Algorithm

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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EXPERIMENTAL STUDY ON THE OVERTOPPING BEHAVIOUR OF STEEP SLOPES – TRANSITION BETWEEN MILD SLOPES AND VERTICAL WALLS

Coastal Engineering Proceedings ◽

10.9753/icce.v33.structures.61 ◽

2012 ◽

Vol 1 (33) ◽

pp. 61

Author(s):

Lander Victor ◽

Peter Troch

Keyword(s):

Slope Angle ◽

Breaking Waves ◽

The Other ◽

Prediction Methods ◽

Wave Overtopping ◽

Wave Energy Converters ◽

Vertical Walls ◽

The One ◽

Steep Slopes ◽

Existing Data

Extensive knowledge is available on the overtopping behaviour of traditional smooth impermeable sea defence structures, such as mildly sloping dikes and vertical walls, both typically featuring a high crest freeboard to reduce wave overtopping. A particular design application emerges in the development of wave energy converters of the overtopping type, where maximisation of wave overtopping is required, i.e. smooth impermeable steep sloping structures with low crest freeboards subjected to non-breaking waves. To date, only relatively limited knowledge is available on the overtopping behaviour of those structures. In this study, the average overtopping rate obtained from new experiments has been analysed and compared with existing prediction methods. This study contributes to a better knowledge on the overtopping behaviour of the steep low-crested structures, which is positioned in between that of mildly sloping dikes and vertical walls on the one hand, and in between that of structures with zero crest freeboards and relatively large crest freeboards on the other hand. The existing prediction methods seem unable to predict the significant effects of the slope angle and small relative crest freeboards on the average overtopping rate accurately. Therefore, a new set of prediction formulae is proposed based on the new experiments combined with existing data from literature. These formulae include wave overtopping at vertical walls subjected to non-impacting waves and at structures with zero crest freeboard.

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IRREGULAR WAVE OVERTOPPING AT VERTICAL WALLS - LEARNING FROM REGULAR WAVE TESTS

Coastal Engineering 2006 ◽

10.1142/9789812709554_0397 ◽

2007 ◽

Author(s):

Karl-Fr. Daemrich ◽

Jens Meyering ◽

Nino Ohle ◽

Claus Zimmermann

Keyword(s):

Regular Wave ◽

Wave Overtopping ◽

Irregular Wave ◽

Vertical Walls

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Determination of Semi-Empirical Models for Mean Wave Overtopping Using an Evolutionary Polynomial Paradigm

Journal of Marine Science and Engineering ◽

10.3390/jmse8080570 ◽

2020 ◽

Vol 8 (8) ◽

pp. 570

Author(s):

Corrado Altomare ◽

Daniele B. Laucelli ◽

Hajime Mase ◽

Xavi Gironella

Keyword(s):

Polynomial Regression ◽

Structural Parameters ◽

Full Range ◽

Empirical Formulas ◽

Wave Overtopping ◽

Evolutionary Polynomial Regression ◽

Local Wave ◽

Vertical Walls ◽

Local Water ◽

Semi Empirical

The present work employs the so-called Evolutionary Polynomial Regression (EPR) algorithm to build up a formula for the assessment of mean wave overtopping discharge for smooth sea dikes and vertical walls. EPR is a data-mining tool that combines and integrates numerical regression and genetic programming. This technique is here employed to dig into the relationship between the mean discharge and main hydraulic and structural parameters that characterize the problem under study. The parameters are chosen based on the existing and most used semi-empirical formulas for wave overtopping assessment. Besides the structural freeboard or local wave height, the unified models highlight the importance of local water depth and wave period in combination with foreshore slope and dike slope on the overtopping phenomena, which are combined in a unique parameter that is defined either as equivalent or imaginary slope. The obtained models aim to represent a trade-off between accuracy and parsimony. The final formula is simple but can be employed for a preliminary assessment of overtopping rates, covering the full range of dike slopes, from mild to vertical walls, and of water depths from the shoreline to deep water, including structures with emergent toes.

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DEVELOPMENT OF WAVE OVERTOPPING MODEL INCORPORATING WATER OVERFLOW FOR VERTICAL WALLS

Coastal Engineering Proceedings ◽

10.9753/icce.v36.waves.3 ◽

2018 ◽

pp. 3

Author(s):

Yoji Tanaka ◽

Katsuyuki Suzuyama ◽

Naoto Higuchi ◽

Hidenori Shibaki

Keyword(s):

Experimental Data ◽

Storm Surge ◽

Vof Method ◽

New Wave ◽

Wave Overtopping ◽

Hydraulic Experiment ◽

Data Provider ◽

Shallow Area ◽

Vertical Walls ◽

Water Overflow

In a situation where water overflow occurs on the seawalls due to a storm surge, generally it is high waves that cause wave overtopping. However, it is common that overflow and overtopping are modeled as separate phenomena, in a situation where both phenomena occur at the same time, the amount of water exceeding the seawalls may not be evaluated correctly. The purpose of this research is to develop a new wave overtopping model including the water overflow for vertical seawalls. The new overtopping model improved the overtopping model of Goda (Goda, 2008: Goda08 model). Goda08 model was developed to adapt for various seawall forms. Goda (2008) insisted it was more accurate than EurOtop model. Nonetheless, Goda08 model has a problem of overestimation in shallow area. Therefore, we tuned the parameters again. It is difficult to reproduce the situation where the overtopping and overflow occur at the same time in a hydraulic experiment. Consequently, CADMAS-SURF which is based on the 2-dimensional non-compressive fluid using the VOF method was used as an experimental data provider for comparative verification of the model.

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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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Large-Scale Experiments of Wave-Overtopping Loads on Walls: Layer Thicknesses and Velocities

Volume 7A: Ocean Engineering ◽

10.1115/omae2018-78104 ◽

2018 ◽

Cited By ~ 2

Author(s):

Lorenzo Cappietti ◽

Irene Simonetti ◽

Andrea Esposito ◽

Maximilian Streicher ◽

Andreas Kortenhaus ◽

...

Keyword(s):

Large Scale ◽

Scale Validation ◽

Irregular Waves ◽

Scale Model ◽

Small Scale ◽

Wave Loads ◽

Wave Overtopping ◽

Large Scale Model ◽

Vertical Walls ◽

Set Up

Wave-Overtopping loads on vertical walls, such as those located on top of a dike, have been investigated in several small-scale experiments in the past. A large-scale validation for a mild foreshore situation is still missing. Hence the WALOWA (WAve LOads on WAlls) experimental campaign was carried out to address this topic. This paper, first presents a description of the large-scale model, the measurement set-up and the experimental methodologies, then it focuses on the layer thicknesses and velocities of the flows created on the promenade by the wave overtopping. A set of resistive wave gauges, ultrasonic distance sensors and velocimeters have been used to conduct these measurements. Preliminary data analysis and results, related to a 1000 irregular waves long test, are discussed. The momentum flux of these flows is studied and its implications, for the wave-overtopping loads acting on the vertical walls, are highlighted.

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UPDATE OF THE EUROTOP MANUAL: NEW INSIGHTS ON WAVE OVERTOPPING

Coastal Engineering Proceedings ◽

10.9753/icce.v35.structures.40 ◽

2017 ◽

pp. 40 ◽

Cited By ~ 1

Author(s):

Jentsje W. Van der Meer ◽

William Allsop ◽

Tom Bruce ◽

Julien De Rouck ◽

Tim Pullen ◽

...

Keyword(s):

Neural Network ◽

Wave Overtopping ◽

Major Improvement ◽

Vertical Walls ◽

Run Up ◽

Steep Slopes

Quite some new insights on wave overtopping were achieved since the first submission of the EurOtop Manual in 2007, which have now resulted in a second edition of this Manual. A major improvement has been made on the understanding of wave by wave overtopping and tolerable wave overtopping that is connected to it. Many videos are available on the overtopping website that show all kind of overtopping discharges and volumes and may give guidance for the user of the Manual. The EurOtop Neural Network and the EurOtop database are improved and extended versions of the earlier NN and CLASH database. New insights and prediction formulae have been developed for very low freeboards; for very steep slopes up to vertical walls; for run-up on steep slopes; for overtopping on storm walls on a promenade; and for overtopping on vertical walls, where overtopping has been divided in situations with and without an influencing foreshore and where the first situation may be divided in non-impulsive and impulsive overtopping.

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