Successive Impact of Two Drops on Surfaces with Various Wettability

Abstract

Lower Weber number impact of two successive water drops on surfaces with various wettability is studied. The drops were made to fall on both hydrophilic and hydrophobic surfaces. The influence of the wettability on the maximum spread after the consecutive impact, are examined in the present work. Results show that the first drop creates a thick film on the surface after the impact, and the film absorbs the energy available for spreading of the second drop. The impacting second drop has to work against the viscous force. The maximum spreading is observed to be higher for the second drop, compared to the first one, on both the surfaces. For the case of the impact on a hydrophilic surface, the study shows that the maximum spreading diameter is higher for both the first and second drops, compared to that on a hydrophobic surface.