Growth of Convective and Absolute Instabilities in Co-flowing Jets

ORAL

Abstract

We have shown recently that the dripping-to-jetting transition in co-flowing liquids is controlled by two non-dimensional numbers: the capillary number (\textbf{\textit{Ca}}$_{out})$ of the outer liquid and the Weber number of the inner liquid (\textbf{\textit{We}}$_{in})$. When jetting is forced by \textbf{\textit{Ca}}$_{out}$, the diameter of the jet narrows in the downstream direction and the drop size scaling is well predicted assuming that the Rayleigh-Plateau instability is convected along the jet to cause its break up. However, when jetting is forced by \textbf{\textit{We}}$_{in}$, the diameter of the jet widens in the downstream direction and the resultant drop size can not be predicted assuming that the Rayleigh-Plateau instability causes the jet to break up. Instead, we believe these jets break due to absolute instabilities.

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Authors

  • Andrew Utada

    Division of Engineering and Applied Science, Harvard University, Cambridge MA 02138, USA

  • Alberto Fernandez-Nieves

    Harvard University, Division of Engineering and Applied Science, Harvard University, Cambridge MA 02138, USA, Division of Engineering and Applied Science. Harvard University

  • David Weitz

    Division of Engineering and Applied Sciences and Department of Physics, Harvard University, DEAS, Harvard University, Cambridge, MA 02138, USA, Harvard University, DEAS, Harvard University, Division of Engineering and Applied Science, Harvard University, Cambridge MA 02138, USA, Division of Engineering and Applied Science. Harvard University, Applied Physics, Harvard University