Study of snow avalanches, ice-blast and collision of icy planetary bodies by high-speed impact and shock-wave experiments of ice

点击翻译按钮获取中文摘要

Detailed processes of ice impact and its relation to shock waves have not been clarified mainly because of various experimental difficulties. However the processess are the most important to understand the mechanism of natural high-speed snow avalanches, practical ice blast techniques, and various planetary collisions of icy bodies. This study was aimed at obtaining the fundamental and common information related to the above-mentioned phenomena by making three different experiments of ice.High-Speed impact experiments were made in a large cold room maintained at -15 degree C.A light gas gun was used to impact ice projentile on ice or snow plates. The impact speed was from 50 to 700 m/s. The experiments at lower speeds were made by dropping ice or snow blocks from a 15-m high tower. Shock tubes were also used to observe the interaction between a shock wave and fine ice particles. In all the three experiments the behavior of ice and snow was observed by high-speed video and image-converter cameras using Schlieren and shadow photography. The analyzes of the obtained datagave many important results such as crack development, ice ejection velocities, etc., the physical implications of which were discussed in each natural and planetary phenomenon.