Regensburg 2004 – wissenschaftliches Programm
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DY: Dynamik und Statistische Physik
DY 15: Fluids I
DY 15.4: Vortrag
Montag, 8. März 2004, 15:15–15:30, H3
On the formation of the primary bead in the droplet detachment process of an elastic liquid — •Christian Wagner1, Yacine Amarouchene2, Daniel Bonn2, and Jens Eggers3 — 1Experimentalphysik, Universität des Saarlandes, Postfach 151150, 66041 Saarbrücken, Germany — 2Laboratoire de Physique Statistique, UMR CNRS 8550, Ecole Normale Superieure, 24 rue Lhomond, 75231 Paris Cedex 05, France — 3School of Mathematics, University of Bristol, University Walk Bristol BS8, 1TW United Kingdom
The droplet detachment process of an elastic liquid is characterized by the suppression of the finite time singularity and appearance of a cylindrical filament between the droplet and the nozzle. Synchronously to the appearance of the filament secondary droplets, so called beads on the string can be observed too. Most reports concern the appearance of beads at the final stage of the droplet detachment process but under certain conditions they are to observe from the beginning of the filament forming process. In this study we present the phase boundaries for these beads. Their appearance is connected with a transition from a symmetric to an asymmetric shape of the droplet neck in the Newtonian regime before the onset of the elastic behavior. This transition is is properly described with a crossover from the symmetric instability solution of the pending droplet to a self similar solution for the pinch of behavior of low viscous Newtonian liquids and the phase boundaries are determined by the ratio of the elongational rate and the Reynoldsnumber.