Drag coefficients of water droplets decelerating in air

Abstract

Abstract The relation of drag coefficient to Reynolds number for decelerating water droplets was tested by releasing into a 50 m s −1 airstream droplets up to 230 μm in diameter. After travelling for 1.83 m in the airstream, the droplets passed through a small hole into still air, and the distances they subsequently travelled could be predicted fairly well by assuming that the effective drag coefficients were about 20 per cent below the steady‐velocity values.