Snapshot from a numerical simulation of a breaking wave (Reynolds number 1.8×105, Webernumber 1.6×103) [31].This simulation was performed on the Mira supercomputer and received a Gallery of Fluid Motion Award by the American Physical Society in 2018.
This project aims to resolve these issues by deploying in-house tools, solvers, and techniques that will readily leverage the capabilities of DOE supercomputing systems to obtain novel statistics and insights into the sub-Hinze-scale bubble population and accompanying gas dissolution.
This is a computational fluid dynamics study focusing on high-fidelity simulations of bubble breakup and gas dissolution in oceanic breaking waves that address energy and environmental challenges through the impact of oceans on weather/climate predictions and offshore wind technologies. The wave-breaking process gives rise to turbulent fluctuations that break up entrained air cavities in quick succession. A wide range of bubble sizes extending down to the Hinze scale—the critical length scale below which turbulent fragmentation ceases—is generated through a breakup cascade. The first objective of this work is to extend fundamental understanding of the bubble fragmentation process to sizes smaller than the Hinze scale, at which bubble formation mechanisms remain a subject of active research. The second objective is to quantify the bubble-induced gas dissolution that is enhanced by the breakup cascade. A major challenge for accomplishing these goals has been the inherent multiscale nature of the problem, which dramatically increases the computational cost and the complexity of the associated physical phenomena.
Understanding sub-Hinze-scale bubble formation mechanisms and quantifying gas dissolution have significant impact on problems of practical importance, such as CO2 transport in the carbon cycle through dissolution of soluble components of the entrapped bubbles, and light and sound scattering. In particular, maritime and climate studies may be informed by the temporal evolution of the bubble size distribution, which enables quantification of the total air–sea interfacial area and size-dependent effects like radiation scattering. This project will yield deeper insights into oceanic bubble breakup and gas dissolution for the development of future predictive technologies for more energetic waves and their associated multiphysics phenomena, such as hydroacoustics, radiation transfer, and scalar transport.
