受堆积体影响的河道3维水流结构试验研究

通过水槽试验研究了河道在堆积体影响下的三维水流结构，采用ADV测量了堆积影响河段的三维流速，分析表明：断面纵向最大流速从堆积体段逐渐偏向右岸，且逐渐向河床底部移动，往下游又逐渐上升并恢复至天然状态。主流受收缩加速影响，越过堆积体后，呈水跃流态。受堆积体挤压流路和水流惯性的影响，主流流速在靠近堆积体略下游位置出现最大值。横向流速在堆积体段出现了正负值交替，某一水深处的流速为零，在该水深的上层，水流偏向堆积体岸流动，在该水深的下层，水流偏向右岸流动，上下层水流出现了反向流动，同时垂向流速在堆积体段也出现了正负值交替，表明在试验段水流呈类螺旋流流态。受堆积体作用，水流从表层到床面不等宽收缩，在堆积体段水流呈逆时针螺旋流与纵向水跃交互作用，水流呈复杂的三维状态。

Experimental Study on Three-dimensional Flow Structure of River Channel Under the Effect of Congeries

Through flume experiment, the three-dimensional flow structure of river channel under the influence of congeries was studied, and the velocity was also measured by ADV. Results show that the maximum longitudinal velocity from the congeries segments gradually moves to the right bank and the bottom of the river bed, and then rise and return to the natural state in the downstream.The main stream is in hydraulic jump affected by accelerated shrinkage of the section over the congeries.Under the influence of the narrow flow path and the inertia,the maximum velocity is in the downstream position of the congeries.Transverse velocity appears positive and negative values in the section of congeries.In the upper layer of the zero, the flow move to the left bank,and in the lower layer,it move to the right bank.The flow in the upper and lower layers appear reverse flow.At the same time, the alternating values are also appeared in the vertical velocity.It appears spiral flow in the test section.By the congeries effect, the flow from the surface to the bed is in different width contraction.Besides,the flow appears the interaction of spiral flow and hydraulic jump.The flow is in a complicated three-dimensional state.