1998 Volume 38 Issue 11 Pages 1233-1241
Experimental studies investigating the break-up of liquid drops impacting on immiscible target liquids have been undertaken. High speed photography has been used to elucidate the mechanisms of drop break-up. Three distinct regimes were identified, i.e., a regime in which drops never break, a regime in which drops show a variable behaviour from no break-up to break-up into multiple droplets, and a regime in which drops always break. The sequence of events that occur on impact can be divided into six stages, namely, impact, spread, contraction, rebound, recovery and penetration. Three different break-up mechanisms were identified, namely, the break-up at the maximum spread of the drop on the cavity floor (perimeter break-up), the break-up at the maximum rebound of the drop (rebounding-jet break-up) and the break-up during penetration through the cavity floor (cavity-pulled break-up).