Harvard University

Abstract:

Recently, Bar-Ziv and Moss discovered a dynamical shape transformation induced in cylindrical lipid bilayer vesicles by the action of laser tweezers. The most striking aspect of this "pearling" instability is that it propagates out from the laser spot via a front moving at constant velocity, at least for early times. Motivated by this phenomenology, we have posed the following question: can the Rayleigh instability of a cylindrical interface between two stationary viscous fluids develop as a propagating front? We provide numerical evidence that this instability can indeed spread behind a constant velocity front, in some cases leading to a periodic sequence of breakup events. We further demonstrate that the results of these calculations are in reasonable quantitative agreement with the marginal stability criterion, which predicts a front velocity as a function of viscosity contrast. Experimental implications are discussed.