Semi-automatic detection of the overtopping waves and reconstruction of the overtopping flow characteristics at coastal structures

Abstract

This paper proposes a semi-automatic and customizable procedure for the identification of the overtopping waves based on a threshold-down-crossing analysis of the sea surface elevation signals. The procedure can be applied to 2D experimental and numerical signals, to emerged and submerged structures, with the same accuracy of a human-supervised analysis. The procedure includes an original and innovative algorithm to compare the water level signals at consecutive gauges and couple the waves propagating in between. The coupling algorithm implies a series of original applications of practical relevance, such as: i) the computation of the wave celerity, which is a crucial parameter for the assessment of the structural stability and the hydraulic vulnerability of the landward area; ii) the estimation of the wave overtopping discharge, which can be obtained by integrating the wave celerities with the surface elevations; iii) the description of the wave overtopping characteristics and their evolution over the structure crest; iv) the evaluation of the volumes lost for percolation in permeable structures. The application to new and literature data and the comparison with well-established formulae prove that the results obtained from the identification and coupling procedures are accurate and reliable.

Individual wave overtopping at coastal structures: A critical review and the existing challenges

“…Formentin and Zanuttigh [23] also developed a semi-automatic procedure including two steps which is applicable for any recorded signal (e.g. overtopping flow thickness, discharge, …) from experimental or numerical tests.…”

“…Whilst the study of wave-by-wave overtopping has increased in recent years e.g. [21][22][23], gaps in knowledge exist in terms of the range of wave-structure parameter combinations that have been studied. Consequently, this paper provides a detailed review of publicly available studies on individual wave overtopping at sea defence structures with the aim of identifying current knowledge gaps to inform future studies.…”

Enhancing climate resilience of vertical seawall with retrofitting - A physical modelling study

“…The Weibull plots of individual overtopping volume can be further analysed to determine the Weibull b parameter (shape parameter in Eq.6) for predicting the maximum overtopping volumes. Previous studies highlighted the changes in the behaviour of Weibull distribution when 'b' parameter is fitted with either upper or lower parts of individual overtopping volumes (Formentin and Zanuttigh, 2019b;Molines et al, 2019b). It was found that fitting the shape parameter b using the highest 10% volumes provides better estimations of the maximum individual overtopping volume, compared to that of highest 50% volumes (Hughes et al, 2012;Zanuttigh et al, 2013).…”

Flow Depths and Velocities across a Smooth Dike Crest

“…The formulations of cu as functions of cot(αoff) further prompted by Bosman et al were fitted again on the values of c instead of u. The wave celerities have been computed using the procedure for the identification and coupling of the overtopping waves developed by references [36,37]. The procedure was applied to the time series of the h-signals registered at D1 and D3, providing as outputs, the time lags for the waves to propagate from D1 and D3.…”