A Numerical Investigation into the Geometric and Kinematic Properties of Incipient Breakers

Abstract

The onset of wave breaking in two-dimensional, two-phase air-water flow is numerically investigated using the open source software Basilisk. This flow is modeled by the Navier-Stokes equations for a single fluid with variable density and viscosity, coupled with a volume-of-fluid (VOF) technique for capturing interface dynamics. Simulations that present the evolution of various energy components under the influence of capillary wave effects are performed and compared to previous numerical simulation data collected. Additionally, a number of simulations are performed to investigate the effects of the Bond number, Bo, and initial wave steepness, ak, on the kinematic and geometric profile of waves in the onset of breaking. It is found that, in both the spilling and plunging breaker cases simulated, increasing steepness led waves to accelerate toward their maximum crest height at faster rates. This trend was not found among non-breaking gravity waves. It was also found that increasing surface tension effectively sped up the breaking process while lowering the maximum crest height.