Microfluidics: Modeling, Mechanics and Mathematics

Chapter 24

The Shape of Drops

24.1 Introduction

Liquids form drops of distinct shapes when deposited on surfaces. This is a phenomenon we know from everyday life, e.g., when observing the shape of raindrops on a window or on the roof of a car. The contour of the drops formed is defined primarily by the size of the drop, the surface tension of the liquid, and the wetting behavior of the liquid on the surface. The theory for deriving the contour was originally described by Bashforth¹ and Adams² in 1883 [1]. It is interesting to note that the equation describing the contour of droplets was the first practical equation to be tackled by a group of numerical schemes referred to as the Adams-Bashforth methods (see section 27.2.6). In this section we ...