Experiment of swing and deformation of a droplet on a horizontal fiber due to crosswind

Abstract

The purpose of this paper is to experimentally investigate the oscillate of a clam-shell shaped droplet on a horizontal fiber by the action of crosswind, quantitatively describe the swing and deformation of the droplet, and analyze the damping force by surface tension. The dynamic images of the droplet are recorded by high-speed cameras, the profile curves in the top view and side view of droplet are both approximated to multiple ellipse arcs. Four kinds of liquids and three nylon fibers are used in the experiments. The experimental results show that the droplet oscillates periodically around the fiber by the flow drag force, the swing frequency is inversely proportional to the droplet mass, but does not increase with Re. In addition to the swing around the fiber, the droplet also oscillates periodically in the radial direction, and the frequency of radial oscillation is higher than that of circular swing, which results in the swing amplitude fluctuation. By the flow pressure, the windward side and the leeward side of the droplet deform asymmetrically, the difference of surface tension force on both sides of the droplet forms a moment against the droplet swing around fiber, the resistance moment increases with the liquid surface tension coefficient and fiber diameter.