--> Air entrainment and bubble statistics in three-dimensional breaking waves
Luc Deike, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, United States, Stephane Popinet, University Pierre and Marie Curie Paris VI, Institut Jean le Rond d'Alembert, Paris, France and Wallace Kendall Melville, Scripps Institution of Oceanography, La Jolla, CA, United States
Abstract:
Wave breaking in the ocean is of fundamental importance for quantifying wave dissipation and air-sea interaction, including gas and momentum exchange, and for improving air-sea flux parametrizations for weather and climate models. Here we investigate air entrainment and bubble statistics in three-dimensional breaking waves through direct numerical simulations of the two-phase air-water flow using the Open Source solver Gerris. As in previous 2D simulations, the dissipation due to breaking is found to be in good agreement with previous experimental observations and inertial-scaling arguments. For radii larger than the Hinze scale, the bubble size distribution is found to follow a power law of the radius, r-10/3 and to scale linearly with the time dependent turbulent dissipation rate during the active breaking stage. The time-averaged bubble size distribution is found to follow the same power law of the radius and to scale linearly with the wave dissipation rate per unit length of breaking crest. We propose a phenomenological turbulent bubble break-up model that describes the numerical results and existing experimental results.
