Impact Dynamics of Suspension Droplets on Liquid Films

Droplet impact on surface is ubiquitous in many industrial applications, such as inkjet printing and spray coating. Rich phenomenon and impact outcomes including bouncing, merging, and splashing have been observed due to the intrinsic complexity stemming from the interplay of surface tension, viscous effect and inertial effect. Impact dynamics of Newtonian droplet on solid and liquid surfaces have been studied extensively. Non-Newtonian effect add another layer of complexity which gives rise to more intricate behaviors. In this talk, I will present our experimental study of suspension droplets impacting on liquid films. Richer phenomenon compared to that with Newtonian liquids have been observed and discussed in terms of a regime map in the Weber number-volume fraction space. Scaling analysis will be discussed to understand the controlling mechanism for the interaction between the suspension behavior and the complex flow field induced by droplet impact.