明渠断面流速与边壁切应力相关的试验研究

Experimental Investigation on Relationship between Velocity and Boundary Shear Stress Distribution in Open channel Flow

根据Ｐｒａｎｄｔｌ理论关于对数流速分布的假定，利用间接测量法测量了相同流量不同水深情况下明渠底部的切应力分布．结果显示，在明渠边壁糙率突然减少的两边流速分布和边壁切应力均有最大值．根据作者的试验结果，给出了槽底平均切应力τ０与明渠流弗汝德数Ｆｒ的相关关系，可供参考．

According to the Prandtl's theory on the supposition of logarithmic velocity distribution, the distribution of boundary shear stress on the bed of the open channel flow can be indirectly measured under the circumstances of the same discharge and the different depth. The result indicates that the velocity and boundary shear stress distribution on the both sides along the wetted perimeter have the maximum value when the roughness coefficient in the wetted perimeter decreases suddenly. In the light of the author's experimental investigation, it points out the relationship between the average shear stress in the bed of flume τ 0 and the Froude number Fr .The relationship is available for reference.