弯道悬沙特性试验研究

本文重点研究弯道悬沙水流的水力特征和泥沙特征变化以及弯道半径对其影响。试验表明,弯道悬沙水流水面横比降与清水相比略有差异,悬沙水流较清水时弯道水面横比降小,弯道半径越大,差异越小。水流入弯道后,水流流速、水流含沙量以及悬沙粒径均进行了重分布。弯道凹凸岸最大流速调整位置随弯道半径的减小而下移。弯道内凸岸含沙量逐渐增加,悬沙粒径也逐渐增粗,在弯道末端断面,凸岸含沙量与凹岸含沙量比值达到最大值,相应凸岸悬沙中值粒径与凹岸悬沙中值粒径比值也达到最大。弯道半径不同,泥沙在横向调整程度也不同。

Experimental study on suspended sediment transport in a bend

The paper presents a study on hydraulic features and suspended sediment characteristics in a bend and their affecting factors. With experiment,it has been found that there is a slight difference of the lateral surface slopes between sediment-laden flow and clear flow in a bend,and the difference becomes smaller with increase of radium. An empirical formula has been established for the relationship between the maximum level difference across the bend and bend radium.As the flow passes through a bend,the flow velocity,suspended sediment concentration and size will be redistributed.The location where a maximum velocity close to either the concave bank or the convex bank will migrate downstream with the decrease of bend radium.Along either the convex bank or the concave bank,sediment concentration and mean sediment particle size increase and reach their peaks just at the end of the bend.Along the bend,the ratio of concentration at the convex to that at the concave,and the ratio of mean sediment particle size at the convex to that at the concave increase and reach their peaks at the end of the bend.With different radium of a bend,the lateral adjustment of suspended sediment varies accordingly.