Statistics of Jet Drop Production

Abstract

Knowledge of the size production flux of primary ocean spray droplets and aerosol particles and its dependence on meteorological and environmental variables is necessary for modeling cloud microphysical properties and the influence of aerosol on radiative processes (Bertram et al., 2018;de Leeuw et al., 2011;Quinn et al., 2015). Biases and uncertainties in predicting sea spray aerosols are related to a lack of fundamental understanding in the production processes of aerosols, and the large range of scales involved going from wave statistics at O (1 km-1 m), to the breaking dynamics at O (1-10 m), air bubble entrainment and bursting at O (microns-mm), which directly impacts our ability to perform weather prediction and earth system modeling (

Role of Contamination in Optimal Droplet Production by Collective Bubble Bursting

“…The vertical upwards motion of the drops is consistent with the jet drop production mechanism (since the expected motion of film drops is mostly sideways). These jet drops explain the narrow peak around 𝐴𝐴 ⟨𝑟𝑟𝑑𝑑⟩ = 250 μm (Figure 4b solid red line), and are well described by the jet drop model (dotted red line) derived from single bubble bursting experiments (Berny et al, 2021;Gañán-Calvo, 2017;Lai et al, 2018). In the clean water case, larger bubbles in the exponentially-tailed surface distribution (Figure 4a dotted red line) are the result of at least one merging event.…”

“…Determining whether the influence of surfactants on the bursting processes results from collective effects or a modification of the individual jetting mechanism remains to be investigated. The resulting drop size distributions can be, and are, rationalized using the framework developed by Lhuissier and Villermaux (2012) and extended by Berny et al (2021), but the knowledge of the surface transfer function and the changes in drop size and number being ejected for given contaminated conditions remain to be theoretically explained. The existence of an optimal production regime controlled by the interplay between the bubble production, bursting and merging rates could explain some of the apparent contradictions in the literature where these characteristics were unknown.…”

“…The production of drops from an assembly of surface bubbles can be analyzed within the framework proposed by Lhuissier and Villermaux (2012) for film drops and extended to jet drops by Berny et al. (2021), which integrates scalings for the number $$n({R}_{s})$$ and size of drops (mean size $$\langle {r}_{d}\rangle ({R}_{s})$$ and distribution $$p({r}_{d}/\langle {r}_{d}\rangle ,{R}_{s})$$) produced by a single bubble bursting over the distribution of bursting bubbles $${N}_{s}({R}_{s})$$: $$${N}_{d}({r}_{d})={\int }_{{R}_{s}}\frac{{N}_{s}({R}_{s})n({R}_{s})}{\langle {r}_{d}\rangle ({R}_{s})}p\left(\frac{{r}_{d}}{\langle {r}_{d}\rangle },{R}_{s}\right)\mathrm{d} {R}_{s}\hspace*{.5em}.$$$ …”

Influence of surfactant concentration on drop production by bubble bursting

“…Nevertheless, despite this dispersion, the trend is clear: (i) surface contamination can prevent the drop production and (ii) when droplets are produced there are less numerous and their number seems to decrease down to a minimum around half the CMC, before increasing again. These results are crucial, they signify that the size distribution of ejected jet drops produced in pure water [24] might be very different than the one produced in water with surfactant. They precise and experimentally validate the recent numerical results of Constante-Amores et al [31] that show that a reduction in the number of ejected droplets arises with surfactant-laden flow due to Marangoni flow.…”

“…Since the pioneer work of D. Blanchard [19] there have been a number of -experimental, numerical and theoretical -combining studies on a single bubble bursting, that brought comprehensive data on the size and speed of the jet drops produced by bubble bursting in water [20][21][22][23]. Applying these results to the bubble size distribution produced under a breaking wave enabled a rough estimation of the statistics of jet drop production [24]. However, the ocean surface is partly covered by a biofilm, which can be modeled with surfactants [25].…”