Spatial Evolution of Skewness and Kurtosis of Unidirectional Extreme Waves Propagating over a Sloping Beach

The understanding of the occurrence of extreme waves is crucial to simulate the growth of waves in coastal regions. Laboratory experiments were performed to study the spatial evolution of the statistics of group-focused waves that have a relatively broad-banded spectra propagating from intermediate...

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Main Authors: Iskander Abroug, Reine Matar, Nizar Abcha
Format: Article
Language:English
Published: MDPI AG 2022-10-01
Series:Journal of Marine Science and Engineering
Subjects:
Online Access:https://www.mdpi.com/2077-1312/10/10/1475
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author Iskander Abroug
Reine Matar
Nizar Abcha
author_facet Iskander Abroug
Reine Matar
Nizar Abcha
author_sort Iskander Abroug
collection DOAJ
description The understanding of the occurrence of extreme waves is crucial to simulate the growth of waves in coastal regions. Laboratory experiments were performed to study the spatial evolution of the statistics of group-focused waves that have a relatively broad-banded spectra propagating from intermediate water depth to shallow regions. Breaking waves with different spectral types, i.e., spectral bandwidths and wave nonlinearities, were generated in a wave flume using the dispersive focusing technique. The non-Gaussian behavior of the considered wave trains was demonstrated by the means of the skewness and kurtosis parameters estimated from a time series and was compared with the second-order theory. The skewness and kurtosis parameters were found to have an increasing trend during the focusing process. During both the downstream wave breaking and defocusing process, the wave train dispersed again and became less steep. As a result, both skewness and kurtosis almost returned to their initial values. This behavior is clearer for narrower wave train spectra. Additionally, the learning algorithm multilayer perceptron (MLP) was used to predict the spatial evolution of kurtosis. The predicted results are in satisfactory agreement with experimental findings.
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spelling doaj.art-4539461d2a2f4b82ac20ea31cfe395112023-11-24T00:44:48ZengMDPI AGJournal of Marine Science and Engineering2077-13122022-10-011010147510.3390/jmse10101475Spatial Evolution of Skewness and Kurtosis of Unidirectional Extreme Waves Propagating over a Sloping BeachIskander Abroug0Reine Matar1Nizar Abcha2Normandie Université, UNICAEN, UNIROUEN, CNRS, UMR 6143 M2C, 14000 Caen, FranceNormandie Université, UNICAEN, UNIROUEN, CNRS, UMR 6143 M2C, 14000 Caen, FranceNormandie Université, UNICAEN, UNIROUEN, CNRS, UMR 6143 M2C, 14000 Caen, FranceThe understanding of the occurrence of extreme waves is crucial to simulate the growth of waves in coastal regions. Laboratory experiments were performed to study the spatial evolution of the statistics of group-focused waves that have a relatively broad-banded spectra propagating from intermediate water depth to shallow regions. Breaking waves with different spectral types, i.e., spectral bandwidths and wave nonlinearities, were generated in a wave flume using the dispersive focusing technique. The non-Gaussian behavior of the considered wave trains was demonstrated by the means of the skewness and kurtosis parameters estimated from a time series and was compared with the second-order theory. The skewness and kurtosis parameters were found to have an increasing trend during the focusing process. During both the downstream wave breaking and defocusing process, the wave train dispersed again and became less steep. As a result, both skewness and kurtosis almost returned to their initial values. This behavior is clearer for narrower wave train spectra. Additionally, the learning algorithm multilayer perceptron (MLP) was used to predict the spatial evolution of kurtosis. The predicted results are in satisfactory agreement with experimental findings.https://www.mdpi.com/2077-1312/10/10/1475skewnesskurtosisJONSWAPPierson–Moskowitzwave trainMLP model
spellingShingle Iskander Abroug
Reine Matar
Nizar Abcha
Spatial Evolution of Skewness and Kurtosis of Unidirectional Extreme Waves Propagating over a Sloping Beach
Journal of Marine Science and Engineering
skewness
kurtosis
JONSWAP
Pierson–Moskowitz
wave train
MLP model
title Spatial Evolution of Skewness and Kurtosis of Unidirectional Extreme Waves Propagating over a Sloping Beach
title_full Spatial Evolution of Skewness and Kurtosis of Unidirectional Extreme Waves Propagating over a Sloping Beach
title_fullStr Spatial Evolution of Skewness and Kurtosis of Unidirectional Extreme Waves Propagating over a Sloping Beach
title_full_unstemmed Spatial Evolution of Skewness and Kurtosis of Unidirectional Extreme Waves Propagating over a Sloping Beach
title_short Spatial Evolution of Skewness and Kurtosis of Unidirectional Extreme Waves Propagating over a Sloping Beach
title_sort spatial evolution of skewness and kurtosis of unidirectional extreme waves propagating over a sloping beach
topic skewness
kurtosis
JONSWAP
Pierson–Moskowitz
wave train
MLP model
url https://www.mdpi.com/2077-1312/10/10/1475
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AT nizarabcha spatialevolutionofskewnessandkurtosisofunidirectionalextremewavespropagatingoveraslopingbeach