人工渠道糙率系数影响因素的试验研究

通过物理模型试验资料分析,探讨了矩形渠道的糙率与渠道水深、弗汝德数的变化规律。分析得出:当底坡不变时,随着弗汝德数Fr的增大,糙率n值逐渐减小。在缓流渠道中,渠道糙率n随弗汝德数Fr变化的速率很快;在急流渠道中,渠道糙率n值随弗汝德数Fr的速率较慢。糙率系数n随水深h的变化关系与流态有关。缓流中,随着水深h的增大,糙率n值减小;急流中,当弗汝德数11.51时,糙率系数n随水深h的增大而增大。

Experiment on influence of factors on roughness coefficient of artificial channel

Through the analysis of test data of physical model, The paper discussed the regularity of roughness changing with water depth and Froude number in rectangular channel. The result showed that when slope is constant,with the increase of Fr the roughness n value decreases gradually. In the slow flow channel,the roughness value of n changes quickly with Fr; in the jet stream channel, the roughness value of n changes more slowly with Fr. That the roughness n changes with water depth relates to flow pattern. With the increase of water depth h, the value of n decreases gradually; when Fr is larger than 1 and less than 1.51, the value of n decreases first with the increase of h and then increases with the increase of h at a certain number; when Fr is larger then 1.51,the value of n increases with the increase of h.