非恒定流作用下的推移质泥沙输移实验研究

Experimental study on bedload sediment transport under unsteady flow

非恒定流条件下的推移质运动研究无论是在泥沙运动理论还是在实际工程应用中,都具有重要的意义.基于波流水槽实验,对不同速度偏度的非恒定流作用下的推移质运动开展研究.主要通过泥沙粒径、速度偏度等因素对输沙率影响分析,探讨了非恒定流作用下的均匀沙与非均匀沙的运动情况,阐述了恒定流与非恒定流对输沙率影响的差异性,建立非均匀沙输移粗细质量比公式.在此基础上开展理论推导,从受力机理上对实验过程进行了分析.实验结果和理论分析表明,相对于恒定流,非恒定流作用下的泥沙颗粒更易起动和输移.

The study of bedload movement under unsteady flow conditions is of great significance both in sediment movement theory and practical engineering applications.Based on the wave-flow flume experiment,the bedload movement under the action of unsteady flow with different speed skewness was studied.Based on the influence of sediment particle size and velocity skewness on sediment transport rate,the motion of uniform sand and non-uniform sand under unsteady flow was analyzed,and the sediment transport rate of steady flow and unsteady flow was described.Meanwhile,the difference in the impact of steady flow and unsteady flow on the sediment transport rate was discussed,and the formula of non-uniform sand transport weight ratio for different sizes was established.On this basis,the theoretical derivation was carried out,and the experimental process was analyzed from the mechanism of force.The experimental results and theoretical analysis show that the sediment particles under the action of unsteady flow are easier to start and transport than the steady flow.