沙粒起动风速研究

STUDY ON ONSET-WIND-SPEED OF BLOWN SAND

在风沙流实验中，发展了设陷井捕集蠕移沙粒的方法来测量各种来流条件下的蠕移沙量，再外推得到流体起动风速．试验表明粗糙度不同的沙平面的流体起动风速相同．文中还给出实验段轴线风速与野外来流摩阻速度之间的对应关系．

By using ‘pitfall’ method, sandtransport-value under different free-stream conditions was measured in wind-tunnel blowing sand experiments. Then the onset-wind-speed of creeping sands can be determined from the transport rate by the extrapolate procedure. The experimental re- sults indicate that the onset speed takes the same value for all the sandy surfaces with different roughness. In addition, the relation between the speed in wind tunnel and the friction speed in desert field was given in the present paper.