副流及其在河床演变中的作用

Secondary Flow and Its Role in River-bed Evolution

副流是指受主要作用力以外各种各样的力所引起的流动，它常具有较大的局部流速和较强的紊动强度，对泥沙的运动和输移起着重要作用；河道、水利枢纽的许多局部冲淤现象都取决于副流。本文对副流现象及其输沙机理作了初步讨论，并进一步探讨了几种常见的副流在河床演变中所起的作用，如弯道环流、回流、折冲水流等。此外，还讨论了副流能量的来源及其转化，指出，若充分利用副流的输沙作用，控制副流的发生及发展，对河床演变可起到趋利避害的作用。

Secondary flow is the one caused by various forces except the main forces, with higher flowvelocity and stronger turbulence intensity, it is of great importance to sediment movement anddelivery. Many partial flushing and silting-up phenomena of river-bed and key hydraulic structures arehinged on the secondary flow. This paper makes a preliminary discussion on secondary flow and itssediment delivery mechanism. in addition to further study of the role of several ordinary kinds ofsecondary flow in river-bed evolution, such as belieal flow, refracted flow. etc.. The source ofhydroenergy of secondary flow and its transformation is also discussed. It is pointed out that fullyusing the role of secondary flow in sediment delivery and controlling its generation and developmentwill produce benefits and avoid disasters in the river-bed evolution.