风沙颗粒起动形式的实验研究

应用高速摄影技术，在风洞实验中获得沙粒运动的连续高速摄影图片，通过时序分段图像叠加方法处理，获得单个粒子的运动轨迹．按照沙粒与气流之间、沙粒与沙粒之间相互作用关系，划分沙粒的起动形式．结果表明，在风沙两相流中的沙粒相存在“自发起跳”、“冲击起跳”和“入射．反弹”等3种起动方式，且3种起动形式在沙粒的起动过程中是交替发生的．

Experimental research on the saltation mechanism of sand grains

Starting mechanism of sand grains is the key issue in Aeolian Physics. A high speed digital photogra- phy was used to record continuous high-speed pictures of sand grain in wind tunnel experiments. Ultimately, the trajectory of a single sand particle was obtained through the subsection addition image processing method. The saltation ways was divided on the basis of interaction between sand grain and air current or in inter-sand grain. The results show that sand grains have saltation ways such as spontaneous take-off, impact tack-off, incident re- bound. And the three starting ways are occurred ahernately.