Experimental Analysis of Wave Overtopping: A New Small Scale Laboratory Dataset for the Assessment of Uncertainty for Smooth Sloped and Vertical Coastal Structures

Abstract

Most physical model tests carried out to quantify wave overtopping are conducted using a wave energy spectrum, which is then used to generate a free surface wave time series at the wave paddle. This method means that an infinite number of time series can be generated, but, due to the expense of running physical models, often only a single time series is considered. The aim of this work is to investigate the variation in the main overtopping measures when multiple wave times series generated from the same spectrum are used. Physical model tests in a flume measuring 15 m (length) by 0.23 m (width) with an operating depth up to 0.22 m were carried out using a stochastic approach on two types of structures (a smooth slope and a vertical wall), and a variety of wave conditions. Results show variation of overtopping discharge, computed by normalising the range of the discharges at a certain wave condition with the maximum value of the discharge in the range up to 10%, when the same wave time series is used, but this range increases to 75% when different time series are used. This variation is found to be of a similar magnitude to both the one found with similar experiments looking at the phenomena in numerical models, and that specified by the confidence bounds in empirical methods.

Numerical and Physical Modelling of Wave Overtopping on a Smooth Impermeable Dike with Promenade under Strong Incident Waves

“…As expected, small deviations were observed between tests, more significant in those cases where the generation system works closer to its operating limits. Thus, calculating the percentage difference between maximum and minimum values measured for the mean wave height, following the formula proposed by [37], differences between 0.4% in the most favourable case and 7.6% in the most unfavourable case are observed, within similar values to those found in the aforementioned work.…”

Quantification of Measurement and Model Effects in Monopile Foundation Scour Protection Experiments

“…Though scale effects are usually perceived as the primary cause of differences between scale and prototype model test results, it is crucial to identify that the scale effects can only be validated and analysed when the measurement effects and the model effects are clearly quantified a priori. Unlike for overtopping events, where repeated tests are quite common for quantifying the model effects [40,41], repeated tests are rarely performed for scour protection stability tests due to the time consumption. De Vos et al (2012) [16] investigated the erosion damage repeatability of monopile scour protection made up with 2.5 layers of armour stones in two environmental conditions, but only three repeated tests were conducted for each condition.…”

Experimental Study on the Influence of Berms and Roughness on Wave Overtopping at Rock-Armoured Dikes

“…Wave overtopping can be characterised by average overtopping discharge (m 3 /s/m or L/s/m), which acts as a key parameter in the design and reinforcement of dikes. Many studies have been conducted in the last decades on wave overtopping (see for instance [6][7][8][9][10][11]) and empirical formulas are available for estimating the average overtopping discharge at dikes (see Appendix A).…”