The Landau–Squire plume. (2nd August 2017)

• Record Type: Journal Article
• Authors: Secchi, Eleonora; Marbach, Sophie; Niguès, Antoine; Siria, Alessandro; Bocquet, Lydéric
• Is Part Of: Journal of fluid mechanics. Volume 826(2017)
• Publication Date: 2017-08-02
• Subjects: jets, -- low-Reynolds-number flows, -- micro-/nano-fluid dynamics; Fluid mechanics -- Periodicals; 532.005
• DOI: 10.1017/jfm.2017.441
• Languages: English
• ISSNs: 0022-1120

Abstract

Abstract : In this paper, we analyse the dispersion of a dye by a Landau–Squire plume, generated by a jet flow emerging from a nanocapillary into a reservoir. We demonstrate analytically that the dye concentration profile exhibits a long-range profile decaying as the inverse of the distance to the origin, whereas the plume shape is only a function of a Péclet number defined in terms of the flow characteristics inside the nanocapillary. These predictions are successfully compared with experiments on fluorescent dye dispersion from nanocapillaries under pressure-driven flow. The plume shape allows extraction of the nanojet force characterizing the Landau–Squire velocity profile for a given pressure drop, with results in full agreement with direct velocimetry measurements and finite-element calculations. The peculiarities of the Landau–Squire plume make it a sensitive probe of the flow properties inside the seeding nanocapillary.