Two successive drops impinging onto a hydrophobic plate

The impact characteristics of two successive water drops impinging onto a hydrophobic plate were experimentally investigated by using the free-falling drop technique incorporated with a drop severance device. The experiments had focused particularly on the influence of the oblique angle (?=15°) of the impinged solid surface on the impact phenomena. The second drop was introduced to achieve two successive drops impingement at three different impinging conditions identified by the time intervals (?t), namely Case 1: ?t1 = 0.6 ms (the leading drop starting spreading); Case 2: ?t2 = 1.0 ms (the leading drop reaching its maximum spreading); and Case 3: ?t3 = 1.7 ms (the leading drop at the shrink process). The experimental result was showed that the oblique angele where the drop rebounded off the surface after spreading for cases of ?t2 and ?t3. This drop took comparatively more time to come back and strike the surface.