Influence of Parapets on Wave Overtopping on Mound Breakwaters with Crown Walls

Abstract

Background literature on the influence of parapets on the overtopping of mound breakwaters is limited. In this study, numerical tests were conducted using computational fluid dynamics (CFD) to analyze the influence of nine crown wall geometries (seven with parapets). The CFD model was implemented in OpenFOAM ® and successfully validated with laboratory tests. A new estimator of the dimensionless mean wave-overtopping discharges (logQ) on structures with parapets is proposed. The new estimator depends on the estimation of logQ of the same structure without a parapet. The effects on wave overtopping of the parapet angle (ε p ), parapet width (w p ), and parapet height (h p ) were analyzed. Low values of ε p and w p /h p ≈ 1 produced the highest parapet effectiveness to reduce the mean wave-overtopping discharges.

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

“…Recent improvements in predictive tools for evaluating mean overtopping discharge from coastal defences have motivated number of studies to examine the effectiveness of retrofitting structures, such as recurve walls and reef breakwaters, in reducing wave overtopping from coastal structures Kortenhaus et al, 2003;Van Doorslaer et al, 2016). A number of studies investigated the effects of recurve retrofitting structures on the mean overtopping discharges from various types of coastal defenses (Molines et al, 2019a;Pearson et al, 2004;Van Doorslaer and De Rouck, 2011). The performance of recurves, described by the mean overtopping discharge, is found to be sensitive to recurve structural dimensions, including overhang length and height (Formentin and Zanuttigh, 2019a;Kortenhaus et al, 2002) and the recurve angle (Martinelli et al, 2018;Van Doorslaer et al, 2015).…”

Crown Wall Modifications as Response to Wave Overtopping under a Future Sea Level Scenario: An Experimental Parametric Study for an Innovative Composite Seawall

“…Therefore, in order to reduce the overtopping at the rear of the structure, the upper crown wall is equipped with a reverse bevel consisting in an isosceles triangular parapet, also denominated "nose" (Figure 1). The effectiveness of the OBREC nose with a pre-fixed geometry was already confirmed by previous studies [19,27]. A clear definition of the hydraulic performance of this nose under different overall dimensions and in the perspective of a SLR scenario is, however, still unknown.…”

“…The reservoir is often equipped with a drainage system providing an uplift pressure saving. In some cases, a parapet on the upper crown wall [27] is conveniently installed. This parapet is aimed to decrease the wave overtopping at the rear side of the structure for very extreme wave conditions.…”

A Validation of Wave Loads on Crest Walls on Top of Composite Breakwaters Using Openfoam

“…For the later region, two levels of refinement were used since high resolution close to the wall is desired for obtaining better prediction of the forces. Antonini et al (2017), Jacobsen et al (2018) and Molines et al (2019) also applied two levels of refinement around the wall. For the other refinement regions, one refinement level was used.…”