阶梯流量冲刷非均匀沙河床累计输沙量等效现象分析OA

Regarding the phenomenon of approximately equal stable cumulative sediment transport volumes un-der the different flow processes and equivalent discharge observed in step-flow scour experiments,the step-flow scour experiments were conducted with riverbeds of wider grain-size distributions the causes and conditions of this phenomenon were analyzed by combining a lag-response model with quantitative indicators of dimension-less stream power and relative mean error.The results show that the cumulative sediment transport volume can be expresses by a lag-response model with constant adjustment parameters when the equivalence condition is satisfied.The greater the dimensionless stream power index value,the smaller the relative mean error in cumu-lative sediment transport volume,and the more significant the equivalent phenomenon becomes,with the two indicators exhibiting a strong power-function relationship.During low-intensity sediment transport in wide-gra-ded riverbeds,the low-frequency pulsating transport of coarse particles caused by the"loss of shelter"effect is the internal factor leading to reduced equivalence in results.