Unsteady sheet fragmentation: from compliance, wetting, non-isolated drop impacts, to secondary drops and contamination

Understanding what shapes the drop size distributions produced from fluid fragmentation is important for a range of industrial, natural and health processes. Fluid fragmentation plays an important role in pathogen transmission  in particular. A particular example is from impacts on contaminated surfaces already, some dry, and others already wet, supporting sessile drops. These are ubiquitous in the field, where plant pathogens are attached to leaves via sticky mucilage requiring dissolution (e.g., spores of rust). The Crescent-moon fragmentation is one of the most efficient fragmentation processes discovered to produce secondary droplets from sessile contaminated fluid, even when the impact from dripping, rainfall, or irrigation is not sufficient to generate secondary droplets (Weber number lower than the splash limit).

In this research axis, a  series of projects involved identification of fragmentation processes most common on plant surfaces of average wetting, ubiquitous in agriculture. This effort was followed by a systematic study of the regimes involved, and the  important physical processes of selection of the droplet sizes and speeds, starting with the fundamental physics of  unsteady fluid sheet fragmentation.  



Bourouiba, L. (2021) The fluid dynamics of disease transmission. Annual Review of Fluid Mechanics. 53:473-508. PDF

Wang, Y. and Bourouiba, L. (2018) Unsteady sheet fragmentation: Droplet sizes and speeds. Journal of Fluid Mechanics. 848: 946-967. PDF

Wang, Y., Dandekar, R., Bustos, N., Poulain, S., and Bourouiba, L. (2018) Universal rim thickness in unsteady sheet fragmentation. Physical Review Letters.120, 204503. PDF

Lejeune, S., Gilet, T., and Bourouiba, L. (2018) Edge-effect: Liquid sheet and droplets formed by drop impact close to an edge. Physical Review Fluids. 3, 083601.

Wang, Y. and Bourouiba, L. (2018) Non-isolated drop impacts. Journal of Fluid Mechanics. 835:24-44. PDF

Wang, Y. and Bourouiba, L. (2017) Drop impact on small surfaces: thickness and velocity profiles of the expanding sheet in the air. Journal of Fluid Mechanics. 814:510-534. PDF

Jung, S.,  Staples, S.,   Dabiri, J.,  Marsden, A.,  Prakash,  M., Davis, K., Shadden,  S., Savin, T., Bourouiba, L., and Sznitman, J. (2016) Research Trends in Biological Fluid Dynamics.  US National Committee on Theoretical and Applied Mechanics (USN/TAM) Invited Report on Recent Trends in Mechanics. Publications of the US National Academies of Sciences, Engineering, and Medicine. PDF

Gilet, T. and Bourouiba, L. (2015) Fluid fragmentation shapes rain-induced foliar disease transmission. Journal of the Royal Society Interface. 12:20141092. PDF

Gilet, T. and Bourouiba, L. (2014) Rain-induced ejection of pathogens from leaves: revisiting the mechanism of splash-on-film using high-speed visualization. Integrative and Comparative Biology. 54:974–984. PDF

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MIT Spotlight; Nautilus science magazine; Science Magazine, Scientific American and some numbers at Altmetric,  including the World Economic Forum, etc.

Video features:

Connecting the Drops

Splash down

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