Individual wave overtopping volumes on mound breakwaters in breaking wave conditions and gentle sea bottoms

Abstract

[EN] Mound breakwaters are usually designed to limit the mean wave overtopping rate (q) or the maximum individual wave overtopping volume (V-max). However, rarely do studies focus on wave overtopping volumes on breakwaters in depth-limited breaking wave conditions. This study analyzes 2D physical tests on mound breakwaters with relevant overtopping rates (0.33 <= R-c/H-m0 <= 2.83) and three armor layers (Cubipod (R)-1L, rock-2L and cube-2L) in depth-limited breaking wave conditions (0.20 <= H-m0/h(s) <= 0.90) and with two bottom slopes (m = 1/25 and m = 1/50). The 2-parameter Weibull distribution was used to estimate V-max* = V-max/(gH(m0)T(01)(2)) with co-efficient of determination R-2 = 83.3%. In this study, the bottom slope (m = 1/50 and m = 1/25) did not significantly influence V-mox or the number of overtopping events, N-ow. During the design phase of a mound breakwater, q is required to use the methods given in the literature to estimate Thus, q must be estimated for design purposes when measured q is not available. In this study, CLASH Neural Network (CLASH NN) was used to estimate q with R-2 = 63.6%. If the 2-parameter Weibull distribution proposed in this study is used to estimate V-max with q estimated using CLASH NN, the prediction error of V-max* is R-2 = 61.7%. With the method presented in this study, the ratio between estimated and measured falls within the range 1/2 to 2 (90% error band) when q is estimated with CLASH NN. The new estimators derived in this study provide good predictions of N-ow and V-max with a method simpler than those in the literature on overtopped mound breakwaters in depth-limited breaking wave conditions on gentle sea bottoms (1/50 <= m <= 1/25).