柔性植被与刚性植被覆盖下坡面流阻力特性研究

Research on Resistance Characteristics of Overland Flow under Cover of Flexible and Rigid Vegetation

主要讨论植被覆盖下的坡面流水力学特征,特别是阻力特征,并比较柔性植被和刚性植被对阻力影响的不同之处,系统地研究了坡面流阻力系数与单宽流量、雷诺数、覆盖度、坡度的关系。研究结果表明:柔性植被覆盖下的坡面流阻力系数随单宽流量变化不显著,但随着坡度的增大,阻力系数是减小的,大坡度小覆盖度下的坡面流阻力系数和雷诺数呈现负相关关系,同时植被覆盖度越大坡面流阻力系数也越大。而刚性植被覆盖下的坡面流阻力系数和坡面单宽流量呈现良好的正向幂函数关系,同雷诺数、植被覆盖度也都有明显的正比关系,同坡度的变化关系和柔性植被覆盖相似,并且刚性植被覆盖下的阻力系数在同等其他条件下明显大于柔性植被覆盖下的阻力系数。

This paper discusses the hydraulic characteristics of overland flow with surface coverage of vegetation, especially the resistance characteristics, compares the difference between flexible and rigid vegetation in their impact on the resistance, and studies the relationship between overland flow resistance coefficient and discharge with single width, Reynolds number, coverage rate and slope systematically. The result is as follows： With surface coverage of flexible vegetation, overland flow resistance coefficient changes very little with the changed discharge, but decreases as the slope gradient increases. The relationship between resistance coefficient and Reynolds number is negative with steep slope and small coverage rate, meanwhile, resistance coefficient increased with coverage rate. However, with surface coverage of rigid vegetation, overland flow resistance coefficient increases with the discharge by power function. The relationship between resistance coefficient and Reynolds number, coverage rate is positive. The change with slope is the same to the flexible state. Resistance coefficient is more with surface coverage of rigid vegetation than flexible one with the other same state in addition.