Events in the shock layer during the interaction of a water drop with a moving object

A steel ball 30 mm in diameter was accelerated to a supersonic velocity (650 m/s) to a collision with a water drop in a free fall. Observations indicate that the rarefaction waves propagating through the liquid upon the collision produce tensile stresses in the liquid which are strong enough to cause cavitation, eventually leading to the formation of a polydisperse phase. It is noted that the characteristic feature of the interaction is the sequential formation of two shock waves which pursue the bow shock through the compressed layer. Relaxation time for the front critical point was found to be 95 microseconds.