Wave run-up and overtopping in rubble-mound breakwaters under oblique wave incidence

Abstract

Former investigations on wave run-up and overtopping of (impermeable and permeable) coastal structures aimed at quantifying the influence of oblique waves on mean overtopping discharge, water layer thickness and velocities by developing empirical formulas of a reduction factor for wave obliquity, γβ (e.g. EurOtop, 2007; Nørgaard et al., 2013). However, most formulas did not consider very oblique waves. The existing data gaps triggered the interest in developing the present experimental work, whose main goal is to contribute to a new whole understanding of the phenomena to mitigate future sea level rise impacts in European coastal structures, including the run-up and overtopping characterization on rough and permeable slopes. The key point is to extend the range of wave steepness values in run-up, overtopping and armour layer stability studies, focusing on oblique extreme wave conditions and on their effects on a sloping breakwater’s trunk armour and roundhead.