Authors:	Theis, Alexander Borrmann, Stephan Mitra, Subir Kumar Heymsfield, Andrew J. Szakáll, Miklós
Title:	A wind tunnel investigation into the aerodynamics of lobed hailstones
Online publication date:	27-Oct-2020
Year of first publication:	2020
Language:	english
Abstract:	The complex surface geometries of hailstones affect their fall behavior, fall speeds, and growth. Systematic experimental investigations on the influence of the number and length of lobes on the fall velocity and the drag coefficient of hailstones were performed in the Mainz vertical wind tunnel to provide relationships for use in numerical models. For this purpose, 3D prints of four artificial lobed hailstone models as well as spheres were used. The derived drag coefficients show no dependency in the Reynolds number in the range between 25,000 and 85,000. Further, the drag coefficients were found to increase with increasing length of lobes. All lobed hailstones show higher or similar drag coefficients than spheres. The terminal velocities of the the hailstones with short lobes are very close to each other and only reduced by about 6% from those of a sphere. The terminal velocities from the long lobed hailstones deviate up to 21% from a sphere. The results indicate that lobes on the surface of hailstones reduce their kinetic energy by a factor of up to 3 compared to a sphere. This has important consequences for the estimation of the destructive potential of hailstones.
DDC:	530 Physik 530 Physics
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 08 Physik, Mathematik u. Informatik
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-5264
Version:	Published version
Publication type:	Zeitschriftenaufsatz
License:	CC BY
Information on rights of use:	https://creativecommons.org/licenses/by/4.0/
Journal:	Atmosphere 11 5
Pages or article number:	Art. 494
Publisher:	MDPI AG
Publisher place:	Basel, Switzerland
Issue date:	2020
ISSN:	2073-4433
Publisher URL:	https://doi.org/10.3390/atmos11050494
Publisher DOI:	10.3390/atmos11050494
Appears in collections:	JGU-Publikationen