MEASUREMNT OF TERMINAL VELOCITY AND DEFORMATION OF FALLING RAINDROPS USING AN ULTRA-HIGH-SPEED VIDEO CAMERA

Abstract

  To measure the diameter and the terminal velocity of natural rainfall drops, consecutive images of falling raindrops were taken by an ultra-high-speed video camera developed by the authors.
  The relationship between the terminal velocity and diameter was obtained from the images, and the behavior of raindrops that moved downward along with time passage was clearly observed from the consecutive images. The terminal velocity obtained from this measurement is smaller than that obtained from Gunn and Kinzer's indoor experiment, in case the equivalent drop diameter is larger than 1.5mm. Since the number of the samples is not sufficient, further experiments are planned to conform the result.