刚性非浸没式植被对弯道水流特性的影响
发布时间：2018-07-24 10:10
【摘要】：该文采用180°U形矩形截面弯道玻璃水槽模拟天然弯道河流,运用声学多普勒流速仪(acoustic doppler velocimeter,ADV)研究刚性非浸没式植被(密度4.47%)对弯道水流纵向流速分布,横向环流及湍流动能(turbulence kinetic energy,TKE)的影响。实验结果表明,当水槽流量较小时,植被对水流的阻碍作用较小,由流速降低而导致的水深增加现象不明显,当水槽流量增大时候,植被对水位的抬升现象明显;水流受植被"阻滞"作用,弯道处纵向流速沿水深分布不再服从"对数型"分布规律,且原本水流受弯道作用后呈现的"上减下增"效果也消失;植被加快了最大流速区向凸岸转移,到达弯道出口时,最大流速区逐渐转移至断面中部区域;在植被的影响下,各断面弯道环流消失;植被会加剧水流紊动效应,导致湍动加剧,TKE增大。上述实验结论将增进研究者对植被对弯道水流特性影响的理解,同时也为泥沙疏浚,河道生态系统恢复提供指导。
[Abstract]:In this paper, a 180 掳U-shaped rectangular section bend glass flume is used to simulate the natural bend river, and the acoustic Doppler velocimeter (acoustic doppler velocimeter) is used to study the longitudinal velocity distribution of rigid unsubmerged vegetation (density 4.47%). The effects of transverse circulation and turbulent kinetic energy (turbulence kinetic energy TKE). The experimental results show that when the flow rate of the flume is small, the effect of vegetation on the water flow is small, and the increase of the water depth caused by the decrease of the flow velocity is not obvious, and when the flow rate of the flume increases, the vegetation uplift the water level is obvious. The water flow is blocked by vegetation, the vertical velocity distribution along the depth of the bend is no longer obeyed the "logarithmic" distribution rule, and the effect of "up, decreasing, decreasing and increasing" after the original flow is affected by the bend is also disappeared. Vegetation speeds up the maximum velocity zone to the convex bank, and when it reaches the exit of the bend, the maximum velocity area gradually shifts to the middle of the section. Under the influence of vegetation, the circulations of each section of the bend disappear, and the vegetation will aggravate the turbulent effect of the flow. The increase of TKE is caused by turbulence. The above conclusions will improve the understanding of the effects of vegetation on the flow characteristics of bends and provide guidance for sediment dredging and restoration of river ecosystem.
【作者单位】： 浙江大学海洋学院;
【基金】：国家自然科学基金(11672267)~~
【分类号】：TV131.3
，
本文编号：2141039
[Abstract]:In this paper, a 180 掳U-shaped rectangular section bend glass flume is used to simulate the natural bend river, and the acoustic Doppler velocimeter (acoustic doppler velocimeter) is used to study the longitudinal velocity distribution of rigid unsubmerged vegetation (density 4.47%). The effects of transverse circulation and turbulent kinetic energy (turbulence kinetic energy TKE). The experimental results show that when the flow rate of the flume is small, the effect of vegetation on the water flow is small, and the increase of the water depth caused by the decrease of the flow velocity is not obvious, and when the flow rate of the flume increases, the vegetation uplift the water level is obvious. The water flow is blocked by vegetation, the vertical velocity distribution along the depth of the bend is no longer obeyed the "logarithmic" distribution rule, and the effect of "up, decreasing, decreasing and increasing" after the original flow is affected by the bend is also disappeared. Vegetation speeds up the maximum velocity zone to the convex bank, and when it reaches the exit of the bend, the maximum velocity area gradually shifts to the middle of the section. Under the influence of vegetation, the circulations of each section of the bend disappear, and the vegetation will aggravate the turbulent effect of the flow. The increase of TKE is caused by turbulence. The above conclusions will improve the understanding of the effects of vegetation on the flow characteristics of bends and provide guidance for sediment dredging and restoration of river ecosystem.
【作者单位】： 浙江大学海洋学院;
【基金】：国家自然科学基金(11672267)~~
【分类号】：TV131.3
，
本文编号：2141039
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