Abyss Aerosols: Drop Production from Underwater Bubble Collisions.

Area of Science:

• Fluid dynamics
• Aerosol science
• Interface science

Background:

• Bubble bursting is a known mechanism for producing airborne particles.
• Existing models focus on surface phenomena like film rupture and jet disintegration.

Purpose of the Study:

• To investigate the origin of submicron drops attributed to surface bubble bursting.
• To identify alternative mechanisms for fine aerosol generation in aquatic environments.

Main Methods:

• Experimental observation of bubble dynamics underwater.
• Analysis of film instability during bubble-bubble collisions.

Main Results:

• A significant fraction of submicron drops are generated internally within bubbles before reaching the surface.
• The flapping instability of the film squeezed between colliding bubbles is identified as the primary source.
• Bubble-bubble collisions play a crucial role in this underwater drop formation.

Conclusions:

• The primary mechanism for generating many submicron drops is underwater, not at the surface.
• Bubble-bubble collisions are a key factor in fine aerosol production.
• This discovery necessitates a revised understanding of air-sea interactions and aerosol transport.