山区宽窄相间河道不同流量下水流结构研究

发布时间：2018-05-21 01:08

  本文选题：宽窄相间河道 + 三维流场　； 参考：《长江科学院院报》2016年08期

【摘要】：为了研究山区河流宽窄相间河段不同流量下水流结构特性,以雅安宝兴河上游河段为研究对象,概化实际河道,并建立三维水流计算模型。结果表明:1小流量下,窄段上游无明显壅水现象,宽窄相间河道显现出与顺直河道相似的特性,随着流量的增加,窄段上游壅水剧烈,宽段到窄段沿程断面平均流速呈现"增加—相对稳定—骤减—相对稳定—增加"的分布规律;2受河宽、壅水和回流影响,不同流量工况下宽段横断面的水流特性分布较窄段更加复杂,且在宽段的壅水区与非壅水区流速分布规律差异亦较大;3不同流量状况下,宽段床面剪切力剧烈变化将造成卵石沿程运动的不连续性,宽段河床呈现周期性往复发展的复归性变形,从而维持了宽段河床结构的稳定,而在窄段,河道在较大的床面剪切力长期作用下,形成了与周围环境相适应的河床结构,以消耗窄段较大的水流能量,从而保护河床的稳定。
[Abstract]:In order to study the characteristics of flow structure under different discharge in mountainous rivers, the upper reaches of Ya'an Baoxing River are taken as the research object, the actual river channels are generalized, and a three-dimensional flow calculation model is established. The results show that there is no obvious backwater in the upper reaches of the narrow section under the small flow of 1: 1, and the characteristics of the broad-narrow interphase channel are similar to those of the straight channel. With the increase of the discharge, the backwater in the upstream of the narrow section is violent. The distribution law of the average velocity along the section from wide to narrow section is "increasing-relatively stable-plummeting-relatively stable-increasing", which is affected by river width, backwater and backflow. Under different flow conditions, the distribution of flow characteristics in wide cross-section is more complex than in narrow section, and the velocity distribution law of backwater area and unbackwater area in wide section is different from that in unbackwater section. The sharp change of shear stress on the wide section of bed will cause discontinuity of pebble movement along the path, and the bed of wide section will exhibit periodic reciprocating deformation, thus maintaining the stability of the structure of the wide section of the river bed, while in the narrow section, the stability of the bed structure will be maintained. Under the long-term action of large shear stress on the bed surface, the river bed structure adapted to the surrounding environment is formed to consume the large flow energy of the narrow section and thus to protect the stability of the river bed.
【作者单位】： 四川农业大学水利水电学院;
【分类号】：TV133
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本文编号：1917046