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

由于各种实验困难，冰撞击的详细过程及其与冲击波的关系尚不清楚。然而，对于理解自然高速雪崩的机制、实用的冰爆技术以及各种行星碰撞冰体来说，这个过程是最重要的。本研究旨在通过三种不同的冰实验，获取与上述现象相关的基本和普遍信息。高速撞击实验在保持在-15℃的大型冷室中进行。使用轻气炮撞击冰块或雪板。撞击速度为50~700m/S。低速试验是从15米高的塔楼上掉下冰块或雪块。激波管也被用来观察激波与冰粒的相互作用。在所有三个实验中，冰雪的行为都是通过高速视频和图像转换相机使用纹影和阴影摄影来观察的。对获得的数据进行了分析，得到了许多重要的结果，如裂缝发展、冰弹速度等，并讨论了它们在每一种自然和行星现象中的物理意义。

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.