Investigating Freely Suspended Water-Drop Interactions with High-Speed Photography

Because direct photographing of the precipitation growth processes is thwarted by the scattered light of cloud droplets and the immense scale over which these processes occur, to obtain photographic evidence of precipitation growth, cloud conditions have been modeled in a laboratory. A large vertical wind tunnel has been used to support thousands of drops in an updraft. To optimize the conditions, a high-speed camera and a lens affording a high degree of variability were selected. To obtain a sharp boundary definition, drops were silhouetted against a frosted glass illuminated from behind with a medium floodlight. A very narrow spotlight was situated 100 degrees from the camera to illuminate the drops being photographed. Most events were filmed at approximately 2.5 m with either a 90, 100 or 120 mm lens at framing rates of 500 frames/s to 4000 frames/s depending on the requirements of the interactions.

Print ISSN

0361-4573

Published

1971-07

Content type

Original Research

DOI

10.5594/J00824