77th Annual Meeting of the APS Division of Fluid Dynamics (November 24, 2024 — November 26, 2024)

P2681589: Turbulent breakup of contaminated bubbles

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Authors

• Tristan Aurégan, Department of Mechanical and Aerospace Engineering, Princeton University
• Emmy Roy, Department of Mechanical and Aerospace Engineering, Princeton University
• Luc Deike, Department of Mechanical and Aerospace Engineering, High Meadows Environmental Institute, Princeton University

DOI: https://doi.org/10.1103/APS.DFD.2024.GFM.P2681589

When a wave breaks in the ocean it entrains large air cavities underwater. These cavities are then broken up into a myriad of bubbles by the turbulent flow created by the breaking wave. This process dramatically increases the surface area of the interface between the atmosphere and the ocean enhances the gas transfer efficiency and is therefore crucial for the uptake of atmospheric carbon dioxide and oxygen by the oceans.The bubble size distribution can be described by two regimes separated by a critical bubble size, the Hinze scale at which capillarity balances the turbulence induced deformation.Surface active agents ('surfactants') are naturally present on the top layer of the ocean and are expected to strongly influence this fragmentation process. We experimentally demonstrate that by adding a small amount of surfactant, the number of sub Hinze scale bubbles can be multiplied by three (visible in the zoomed in views below), dramatically increasing the exchange surface area and the associated mass fluxes between the atmosphere and the ocean.