Wave Breaking Characterization in Dam-Break Flows over Submerged Obstacles: Effects of Obstacle Height and Location

This study seeks to characterize wave breaking in gravity-driven dam-break flows. Using high-fidelity two- and three-dimensional Large Eddy Simulation (LES), we explore the dynamics of wave–obstacle interactions beyond the classical smooth sea-bed scenario. The collapsing water column passes over submerged rectangular obstacles, and the focus is on how variations in obstacle height and location influence wave breaking behavior. The numerical framework enables detailed resolution of turbulent structures, vorticity generation, and free surface deformation for studying breaking mechanisms. A comprehensive parametric sweep over obstacle height, streamwise location, and reservoir aspect ratio reveals a rich spectrum of breaking regimes that depend strongly on topographic modifications. Taller or more upstream obstacles tend to induce plunging or collapsing breakers characterized by steep wave faces, overturning jets, and substantial air entrainment. Shorter or further downstream obstacles generate spilling breakers with more gradual energy dissipation through foam cascading down the wave face. In certain configurations, non-breaking undular fronts are observed, exhibiting surface oscillations without complete wave collapse. The classification follows established criteria: spilling breakers demonstrate progressive energy release through turbulent mixing; plunging breakers show rapid energy dissipation via entrapped air pockets beneath overturning crests; and collapsing breakers represent an intermediate regime with partial crest failure. These results provide a quantitative framework for characterizing, understanding and predicting wave breaking patterns induced by abrupt seabed topographic changes. The findings have broad relevance for tsunami impact modeling, submerged coastal defenses, and the design of laboratory-scale experiments aimed at studying gravity wave–induced breaking in controlled environments.