Numerical Investigation of Low-Viscosity Drop Breakup in a Contracting Flow

By using an accurate indirect boundary element method, the break- up of a low-viscosity-ratio isolated drop is investigated numerically in a contraction flow at vanishing Reynolds numbers. A practical mathematical method is constructed to detect the asymptotic behavior of the maximum curvature at the point of pinch-off and is used to predict an impending breakup and the breakup time. The 3-D numerical simulation presented here can accurately capture not only the primary breakup of a low viscosity drop as it moves through a constricted geometry, but also secondary breakups and the presence of a set of satellite drops. The results agree qualitatively with laboratory ex- periments and two-dimensional simulations, but provide more details, aiding the understandiing of the process of low-viscosity-ratio drop breakup in an arbitrarily shaped confined outer flow.