Pinch-off of microfluidic droplets with oscillatory velocity of inner phase flow.

摘要: When one liquid is introduced into another immiscible one, it ultimately fragments due to hydrodynamic instability. In contrast neck pinch-off without external actuation, the viscous two-fluid system subjected an oscillatory flow demonstrates higher efficiency in breaking fluid threads. However, underlying dynamics of this process less well understood. Here we show that neck-thinning rate accelerated by amplitude oscillation. By simply evaluating momentum transfer from derive a dimensionless pre-factor quantify pinch-off. Our data ascribes acceleration non-negligible inner inertia, which neutralizes phase stress retards Moreover, characterize equivalent behavior between actuated and its unactuated counterpart with decreased viscosity ratio. Finally, demonstrate oscillation capable modulating satellite droplet formation shifting location. study would be useful for manipulating fluids at microscale forcing.