Experimental investigation of dynamics of primary and satellite droplet formation

In this paper, the dynamics of drop formation at low Weber numbers (We = ρV2D/σ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\rho V^{2} D/\sigma$$\end{document}) were investigated experimentally. Deionized (DI) water drops dripping from nozzles were photographed using a high-speed camera. The studied drop parameters mainly include the limit length of the filament, the thickness of the neck, the position of the neck, the size of the drop and the satellite droplet, and the movement trend of the satellite droplet. We found that the wettability of the needle nozzle mainly influences the dynamic dripping process of drops by changing the diameter of the contact circle of the three phases of gas, liquid, and solid. The transition of the satellite droplet behavior with the flow velocity and the diameter of the contact circle was further explored, and it was found that there are multiple critical transition states in the experimental parameter space. The change in the movement trend of satellite droplets is the result of the competition between surface tension and gravity. It is also affected by the flow rate, droplet oscillation, and interaction time.