The Hydraulic Characteristics Research On Typical Curved And Branch Channel In The Middle And Down Stream Of Yangtze River

Curved riverway and central decharge almost appeared in main stream of the middle and down stream of changjiang river. Over a long period of time, some phenomena existed in branch riverway, such as mainstream sway, the main alternate with branch, bank flushing, and the central decharge change frequently. And after waterstoring and dam up the sand by Three Gorges Project, the reorganization of discharge of water and sand condition would make the riverbed changing obviously in the downriver of dam. And the change would have a big impact on the safety of dike, obtain water guarantee and the clear shipping. So it is important to do researches on the representative curved and branch riverway characteristics in the middle and down stream of changjiang river.First, the article based on the realize of current characteristics on curved and branch riverway in and abroad, and do the data analysis of curved and branch riverway in the middle and down stream of changjiang river, 4 fixed-bed models have been selected combined with reach of Yaojian, measured three-dimensional velocity of flow with high-class Acoustic Doppler Velocimeter (short for ADV), made a detailed test on shape of surface, current velocity distributes, driving force axes, turbulence characteristics of representative curved and branch riverway, and work out surface shape distributing of curved and branch riverway; study out the surface curve formula of right branch in conditions of Mainly right branch; and draw out velocity of curved and branch riverway, the chart of flow field distributing, driving force axes, the circumfluence chart of transect velocity; work out the plane isoline pulsant chart of kinetic energy; transform the region distributing from time to frequency of instantaneous velocity. And in the article it discussed the curved and branch riverway current effect on decharge and sea-route changing. Through the general comparison with trial characteristic research find that the descending order of the stability of central decharge: Mainly right Branch, Mainly left Branch, balance period.Finally, inspected the test result with two-dimensional numerical value analog computation.