Liquid Thread Breakup and the Formation of Satellite Droplets

TL;DR

This paper investigates the breakup of liquid threads into droplets using many-body dissipative particle dynamics, revealing power-law relationships for breakup wavelength and satellite droplet formation influenced by fluid properties.

Contribution

It introduces a novel simulation approach to quantify breakup characteristics and satellite droplet formation in liquid threads, linking these to fluid dynamic parameters.

Findings

Breakup wavelength follows a power-law dependence on the Ohnesorge number.

Number of satellite droplets decays with a power-law related to Ohnesorge and thermal capillary numbers.

Satellite droplet formation results from advection of pinching points in thinning necks.

Abstract

The breakup of liquid threads into smaller droplets is a fundamental problem in fluid dynamics. In this study, we estimate the characteristic wavelength of the breakup process by means of many-body dissipative particle dynamics. This wavelength shows a power-law dependence on the Ohnesorge number in line with results from stability analysis. We also discover that the number of satellite droplets exhibits a power-law decay with exponent $0.72 \pm 0.04$ in the product of the Ohnesorge and thermal capillary numbers, while the overall size of main droplets is larger than that based on the characteristic wavelength thanks to the asynchronous breakup of the thread. Finally, we show that the formation of satellite droplets is the result of the advection of pinching points towards the main droplets in a remaining thinning neck, when the velocity gradient of the fluid exhibits two symmetric maxima.