风沙流冲击角度对其侵蚀床面能力的影响

Wind Tunnel Experiment on the Effect of Sand Particles to the Erosion of Bed-surface with Different Angles

以黄土作为风蚀床面材料,通过风洞实验来揭示冲击角度对风沙流侵蚀能力的影响。在净风条件下,无论风速多大,不会产生风蚀;蠕移砂粒对床面的摩擦侵蚀量也很少,在0.27~1.33 g/（min.m2）;跃移砂粒对床面的冲击侵蚀率较大,侵蚀量随风速呈指数增加。冲击角度对风蚀率的影响很大,在风速为10 m/s时,倾角30°样品的风蚀率是0°时的2.66倍,在风速为15 m/s时,倾角30°样品的风蚀率是0°时的6.6倍,风速越大,相差倍数越大。在风速大于12 m/s时,风蚀率随样品放置角度（床面的坡度）的增大而增大,尤其是0°~20°时,风蚀率随角度增加的速率很快。在低风速条件下（〈12 m/s）,存在一个最大侵蚀角度,这个角度在30°左右。

In this study tested in wind tunnel by , the effect of sand particles to the erosion rate of bed-surface with different angles was aking loess as the experimental material. The results show that the wind without carrying sand can not erode the samples whatever how wind velocity is. Erosion rate of creeping sand particles is very little, only ranging from 0.27 g/（ min · m2） to 1.33 g/（min · m2）. Sample erosion is mainly caused by saltation sand particles, and the main factors affecting erosion are wind velocity and obliquity of samples. The erosion rate is exponentially increased with increasing wind velocity. Wind erosion rate is strongly affected by impact angle. When the sample obliquity is 30°, the wind erosion rate is 2.66 times of that when the sample obliquity is 0° under wind velocity of 10 m/s. When the sample obliquity is 30° , the wind erosion rate is .6.6 times of that when the sample obliquity is 0° under wind velocity of 15 m/s. The experiment also reveals that the wind erosion rate is increased with increasing the sample obliquity, especially in a sample obliquity range of 0° - 20°. Wind erosion rate can reach a maximum value when the sample obliquity is about 30° under low wind velocity （ 〈 12 m/s）.