Rainfall Deposit on a Wall of a Building in a Storm

Abstract

Rainfall on a vertical wall of a building in a storm is studied. Raindrops in wind are carried horizontally at the speed of the wind; and they fall with a terminal speed determined by their sizes. The deposition efficiency of rain water on a building was estimated from analogy with the deposition of fog particles on an obstacle in wind, and was tested by field experiments. The field experiments show that the efficiency of deposition is about unity in the case of heavy rain and high wind.