The contact time of droplet impacting on surfaces involves in the extent of transformation between the droplet's surface energy and kinetic energy. Based on the axisymmetric assumption, the theoretical prediction of the contact time is regardless of impacting velocity of the droplet. In order to further reduce the contact time, a novel superhydrophobic surface with a macro-textured ridge was proposed by Bird et al . to generate asymmetric bouncing behaviors of a droplet. In the present study, a detailed numerical simulation was carried out to investigate the bouncing dynamics of the impacting process of droplets on surface with a macro-textured ridge at various Weber (We) numbers by adopting many-body dissipative particle dynamics (MDPD). The bouncing dynamics of droplets can be mainly divided into two types, i.e. jug-like behavior with asymmetric retracting velocity and wing-like behavior with rotation of the sub-droplets. The angular velocity of droplets during rebounding is crucial for the corresponding contact time, where the step-like angular velocity at different We numbers are observed. Finally, a brief theoretical analysis was provided to reveal the critical We number and the limitation of contact time for the wing-like state. This work is helpful in understanding the reduction of contact time for droplet impacting on a macro-textured superhydrophobic surface, meanwhile, it offers a guidance for surface structural design where enough angular velocity of droplets should be produced during rebounding if the contact time needs to be decreased.
ASJC Scopus subject areas
- Computer Science(all)