The aerodynamics of oblate hailstones

✍ Scribed by S. Thwaites; J. N. Carras; W. C. McKlin

• Publisher: John Wiley and Sons
• Year: 1977
• Tongue: English
• Weight: 523 KB
• Volume: 103
• Category: Article
• ISSN: 0035-9009
• DOI: 10.1002/qj.49710343819

✦ Synopsis

Abstract

Artifical hailstones having shapes and structures closely resembling natural oblate hailstones have been grown in a vertical icing tunnel. These hailstones were grown by spinning them about the minor axis and at the same time causing the minor axis to move in a conical manner about the horizontal, a motion termed symmetric gyration. It is inferred that natural oblate hailstones undergo essentially this type of motion during growth. the oblateness of the hailstones is determined by the angle of the cone and the observed oblateness of natural hailstones indicates that the most common half‐angles of the cone lie in the range 20° to 45°. the lobes in the hailstones grow in the local direction of impingement of the accreted droplets and this produces characteristic non‐radial divergent lobes along the minor axis.