Drop shape and erosivity part I: Experimental set up, theory, and measurements of drop shape

Simulated raindrops falling in still air have a shape that is mainly determined by surface tension and hydrostatic pressure. Drops released from capillary tips show an initial shape variation ranging from prolate to oblate but eventually this oscillation is damped. At terminal velocity drops have attained equilibrium and have an oblate shape. Measurements of the shape of simulated rain drops produced by capillary tubes were made using a simple, newly‐developed photographic set up. The measurements showed that models describing the oscillation frequency and amplitude of drops falling at terminal velocity can also be applied to the simulated drops. A comparison is made between the shape of raindrops in natural storms and simulated drops. Recommendations are given regarding fall heights in simulation in relation to the drop shape in nature.