中文摘要：

用高速摄像和加速度传感器观测方法研究物体在重力加速度作用下撞击二维颗粒床并在其中穿行的运动过程。由高速摄像可以清楚地观察到床颗粒受撞击后的位移分布情形,揭示了颗粒床被流化的区域及程度和可能产生喷流的物理机制。流化区域仅限于撞击物路径附近,反应了颗粒介质的强耗散特性。通过加速度传感器直接测量撞击物在运动过程中所受阻力,与在液体中穿行阻力进行了比较。相关的实验数据反映了在这样的二维体系中,撞击物受到不可忽略的与速度相关的阻力作用。

英文摘要：

Projectile impact and penetration in a 2D granular bed under the acceleration due to gravity was been studied by fast video photograph and acceleration sensors. The distribution of displacement of the granular bed after impact can be clearly observed by high-speed video photograph. Granular jet formation and the penetration regime of the projectile shown in the experi- ment, reflect the properties of energy dissipation of granular mediums. The acceleration sensor can directly measure drag forces of the projectile in the movement, and these forces compare with hydrostatic drag forces during penetration. Experimental data obtained by comparison showed that considerable drag forces act on the projectile and these forces are related to velocity.