Analytical Calculation of Falling Droplets from Cylindrical Capillaries

Abstract

Existing investigations to estimate different properties of falling droplets are based on empirical data or complex mathematical approaches. This paper presents a new simple analytical approach to calculate selected properties of droplets, in particular the volume and frequency of falling droplets, out of a thin vertical cylindrical capillary. The fluid-reservoir is located above the capillary and provides a constant flow into the droplet. This leads to drop formation times less than one second. The results of the calculation are validated by numerical simulations and experiments.