Turbulence and energy dissipation mechanisms in steady spilling breaking waves induced by a shallowly submerged hydrofoil

Abstract

Wave breaking is one of the most violent phenomena in air-water interface interactions that need to be considered in ship and offshore structures design. Spilling breaking waves induced by a shallowly submerged hydrofoil are investigated using a Navier-Stokes solver for two-phase flow. Computed wave profiles and velocity fields are compared with experimental results and good agreement obtained. A related non-breaking wave case is designed based on the same numerical model to distinguish the hydrodynamic characteristics of the spilling breaking waves and allow investigation of effects on waves downstream. The velocity profile and turbulence intensity profiles at different sections from the two cases are compared with measurement data, where available. A detailed comparison of the wave-breaking process compared to the non-breaking wave is provided. Further, the energy dissipation processes for the two cases are analyzed and the ratio of the turbulent dissipation rate to the total energy dissipation calculated. It is shown that a large amount of energy is dissipated in the region of the breaking wave when compared to the non-breaking wave. Approximately 12% of the total energy dissipation may be attributed to the wave-breaking process, induced by energy redistribution and additional contributions to turbulent fluctuations in the breaker.