An analytic model of sound production by raindrops

Observations of the cavity produced by a droplet of rain falling on a plane water surface show that the cavity often takes the form of an inverted cone. In the present paper we discuss a simple analytic expression for the corresponding fluid flow. The main source of rain noise has been found to occur when the flow entrains an air bubble at the vertex of the cone. In this paper we show that the magnitude of the sound produced by the fluid flow in the present model is consistent with observation.