Satellite drops: Unexpected dynamics and change of scaling during pinch-off

During drop formation from a tube, a thin liquid thread-the precursor to satellites-connects an about-to-form primary drop to the remainder of the liquid hanging from the tube at the incipience of breakup. Whether the thread, once it detaches from the primary and pendant drops, evolves into a sphere or breaks into several subsatellites has heretofore been inadequately explored due to experimental and theoretical difficulties. These challenges are resolved here with an ultrafast digital imaging system and a novel computational algorithm. New findings range from the discovery of unexpected dynamics to the first demonstration of the transition from one scaling law governing interface rupture to another. (C) 2001 American Institute of Physics.