Journal of Colloid and Interface Science, Vol.286, No.2, 661-669, 2005
Impact of droplets onto inclined surfaces
Drop impacts onto dry walls and liquid films at low impact angles and low normal Weber numbers are experimentally investigated. Measurements were performed using a high spatial resolution CCD camera and short exposure times, yielding both qualitative and quantitative information about the impact. Whereas a droplet generally deposits oil the surface for high impact angles, a rebound can occur at lower angles and for smooth or wetted surfaces. No rebound is observed for rough surfaces. A low viscous liquid (water) will either rebound or deposit on smooth or wetted surfaces. A high viscous liquid (glycerin) may also disjoin into two droplets, depending oil the impact angle. A correlation is presented for the size of the secondary droplet. A further correlation quantifies the critical impact angle at which rebounding first occurs in terms of the normal Weber number. (c) 2005 Elsevier Inc. All rights reserved.