Wave breaking over submerged obstacles in gravity-driven dam-break flows: A classification framework

This study presents a systematic classification of wave-breaking regimes induced by gravity-driven dam-break flows interacting with submerged obstacles. High-fidelity large-eddy simulations are employed to resolve the transient, nonlinear, and viscous dynamics of the flow. A series of two- and three-dimensional simulations is conducted across a range of initial water depths and aspect ratios. These simulations reveal distinct wave-breaking behaviors—ranging from spilling and surging to collapsing and plunging breakers. We propose a classification framework based on dimensionless parameters related to particle acceleration, velocity, and trajectory slope. These descriptors are more appropriate than conventional wave steepness metrics, particularly when wavelength is neither well-defined nor unique. The study further quantifies potential–kinetic energy exchange, energy dissipation, and slamming forces exerted on the downstream wall. Although idealized, the submerged obstacle configuration captures essential physical processes relevant to both natural and engineered coastal systems. Overall, this work offers a unified framework linking dam-break hydraulics to coastal wave-breaking dynamics, with implications for hazard assessment, sediment transport, and early stage tsunami modeling.