FRAGMENTATION AND SPREADING OF A METEOR-LIKE OBJECT

Abstract

The phenomenon of fragmentation and spreading of a high-speed flying object resembling a meteorite is studied experimentally and theoretically. Experimentally, a model made of graphite is launched in a ballistic range and is made to fragment and spread. The flow field produced by the cloud of the fragments is observed optically. The observed deceleration and spreading behavior is numerically reconstructed using computational-fluid-dynamic calculations, applying an improved meteoroid fragmentation theory. The existing meteoroid fragmentation theory is improved by introducing the hypothesis that the incubation process of the pressurized fluid permeating through the fragment precedes the splitting process. The incubation time is determined by the ratio of permeability of the fragment to the fluid's viscosity and is much longer than the time for splitting given by the existing theory. Agreement is obtained between the observed and calculated behavior of the fragment cloud by appropriately choosing this ratio.