Seven ice mass balance instruments deployed near 83°N on different first‐year and second‐year ice floes, representing variable snow and ice conditions, documented the evolution of snow and ice conditions in the Arctic Ocean north of Svalbard in January–March 2015. Frequent profiles of temperature and thermal diffusivity proxy were recorded to distinguish changes in snow depth and ice thickness with 2 cm vertical resolution. Four instruments documented flooding and snow‐ice formation. Flooding was clearly detectable in the simultaneous changes in thermal diffusivity proxy, increased temperature, and heat propagation through the underlying ice. Slush then progressively transformed into snow‐ice. Flooding resulted from two different processes: (i) after storm‐induced breakup of snow‐loaded floes and (ii) after loss of buoyancy due to basal ice melt. In the case of breakup, when the ice was cold and not permeable, rapid flooding, probably due to lateral intrusion of seawater, led to slush and snow‐ice layers at the ocean freezing temperature (−1.88°C). After the storm, the instruments documented basal sea‐ice melt over warm Atlantic waters and ocean‐to‐ice heat flux peaked at up to 400 W m−2. The warm ice was then permeable and flooding was more gradual probably involving vertical intrusion of brines and led to colder slush and snow‐ice (−3°C). The N‐ICE2015 campaign provided the first documentation of significant flooding and snow‐ice formation in the Arctic ice pack as the slush partially refroze. Snow‐ice formation may become a more frequently observed process in a thinner ice Arctic.
At the end of their life, surface bubbles burst and emit aerosols, which drastically impact exchanges in liquid as well as in pathogens or flavors with the surrounding atmosphere. This exchange depends on the thickness of the liquid film and is thus linked to the bubble drainage dynamics and to their lifetime. In this article, we propose to explore both feature for big surface bubbles depending on their size. We also explore the impact of atmospheric humidity by a careful control and systematic variation of the relative humidity. We show that a model including both capillary and gravity driven drainage gives a prediction of the bubble lifetime in line with experiments provided convection is taken into account to calculate the evaporation rate. arXiv:1907.09734v1 [cond-mat.soft]
Although soap films are prone to evaporate due to their large surface to volume ratio, the effect of evaporation on macroscopic film features has often been disregarded in the literature. In this work, we experimentally investigate the influence of environmental humidity on soap film stability. An original experiment allows to measure both the maximum length of a film pulled at constant velocity and its thinning dynamics in a controlled atmosphere for various values of the relative humidity [Formula: see text]. At first order, the environmental humidity seems to have almost no impact on most of the film thinning dynamics. However, we find that the film length at rupture increases continuously with [Formula: see text]. To rationalize our observations, we propose that film bursting occurs when the thinning due to evaporation becomes comparable to the thinning due to liquid drainage. This rupture criterion turns out to be in reasonable agreement with an estimation of the evaporation rate in our experiment.
Surface bubbles are present in many industrial processes and in nature, as well as in carbonated beverages. They have motivated many theoretical, numerical and experimental works. This paper presents the current knowledge on the physics of surface bubbles lifetime and shows the diversity of mechanisms at play that depend on the properties of the bath, the interfaces and the ambient air. In particular, we explore the role of drainage and evaporation on film thinning. We highlight the existence of two different scenarios depending on whether the cap film ruptures at large or small thickness compared to the thickness at which van der Waals interaction come in to play.
The prediction of the lifetime of surface bubbles necessitates a better understanding of the thinning dynamics of the bubble cap. In 1959, Mysels et al. [Soap Films: Studies of Their Thinning and a Bibliography (Pergamon, New York, 1959)], proposed that marginal regeneration, i.e., the rise of patches thinner than the film should be taken into account to describe the film drainage. Nevertheless, an accurate description of these buoyant patches and of their dynamics as well as a quantification of their contribution to the thinning dynamics is still lacking. In this paper, we visualize the patches, and show that their rising velocities and sizes are in good agreement with models respectively based on the balance of gravitational and surface viscous forces and on a Rayleigh-Taylor-like instability. Our results suggest that, in an environment saturated in humidity, the drainage induced by their dynamics correctly describes the film drainage at the apex of the bubble within the experimental error bars. We conclude that the film thinning of soap bubbles is indeed controlled, to a large extent, by marginal regeneration in the absence of evaporation.
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