河床形态对连续弯曲河道水流结构的影响

IF 3.3 3区 环境科学与生态学 Q2 ENVIRONMENTAL SCIENCES
Yujiao Liu, Yuanfang Chai, Minghui Yu, Yinjun Zhou
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引用次数: 0

摘要

简介以凹凸河床形态为特征的条形河床和潭形河床是弯曲河道的典型特征。河床形态对弯曲河道的水流结构有重要影响:方法:基于物理模型试验数据,本研究采用 RNG k-ε 模型和 VOF(流体体积)方法对连续弯曲河道中的水流进行了三维数值模拟:结果:通过比较平床渠道与带栅栏和水池渠道的流动结构变化,结果表明栅栏和水池的存在导致上游弯道入口附近凸岸一侧的纵向流速增加,而在下游弯道则相反。高速区域沿着弯道向凹岸缓慢移动。点状条石的存在削弱了上游弯道凸岸附近的环流,导致环流强度降低。在弯道顶点,环流强度的降幅最大(-23.91%)。在下游弯道,来自上游弯道的剩余环流在水池中的衰减速度较慢,影响距离较大,从而增加了下游弯道的环流强度。靠近弯道入口处的断面显示出最大的环流强度增幅,增幅为 128.18%。河床地形的不均匀性增加了下游弯道河床剪应力的不均匀性:本研究结果有助于加深对天然弯曲河流复杂水流结构和演变趋势的理解,为弯曲河道的治理提供科学依据。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
Influences of channel bed morphology on flow structures in continuous curved channels
Introduction: The formation of bars and pools, characterized by concave and convex bed morphology, is a typical feature of curved rivers. The channel bed morphology has a significant influence on the flow structures in curved channels.Methods: Based on data from physical model experiments, this study employs the RNG k-ε model and the VOF (Volume of Fluid) method to perform three-dimensional numerical simulations of flow in continuous curved channels.Results: By comparing the variations in flow structures between channels with a flat bed and channels with bars and pools, the results show that the presence of bars and pools leads to an increase in longitudinal flow velocity on the convex bank side near the entrance of the upstream bend, while in the downstream bend it is opposite. The high-velocity region shifts slower towards the concave bank along the bend. The presence of point bars weakens the circulation near the convex bank in the upstream bend, resulting in a smaller circulation intensity. The decrease in circulation intensity is the largest (−23.91%) at the apex of the bend. In the downstream bend, the remaining circulation from the upstream bend attenuates slower in the pool and has a greater impact distance, increasing the circulation intensity in the downstream bend. The section near the bend entrance shows the largest increase in circulation intensity, with a rate of 128.18%. The unevenness of the bed topography increases the unevenness of the bed shear stress in the downstream bend.Discussion: The findings of this study contribute to a deeper understanding of the complex flow structures and evolution trends in natural curved rivers, providing scientific basis for the management of curved river channels.
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来源期刊
Frontiers in Environmental Science
Frontiers in Environmental Science Environmental Science-General Environmental Science
CiteScore
4.50
自引率
8.70%
发文量
2276
审稿时长
12 weeks
期刊介绍: Our natural world is experiencing a state of rapid change unprecedented in the presence of humans. The changes affect virtually all physical, chemical and biological systems on Earth. The interaction of these systems leads to tipping points, feedbacks and amplification of effects. In virtually all cases, the causes of environmental change can be traced to human activity through either direct interventions as a consequence of pollution, or through global warming from greenhouse case emissions. Well-formulated and internationally-relevant policies to mitigate the change, or adapt to the consequences, that will ensure our ability to thrive in the coming decades are badly needed. Without proper understanding of the processes involved, and deep understanding of the likely impacts of bad decisions or inaction, the security of food, water and energy is a risk. Left unchecked shortages of these basic commodities will lead to migration, global geopolitical tension and conflict. This represents the major challenge of our time. We are the first generation to appreciate the problem and we will be judged in future by our ability to determine and take the action necessary. Appropriate knowledge of the condition of our natural world, appreciation of the changes occurring, and predictions of how the future will develop are requisite to the definition and implementation of solutions. Frontiers in Environmental Science publishes research at the cutting edge of knowledge of our natural world and its various intersections with society. It bridges between the identification and measurement of change, comprehension of the processes responsible, and the measures needed to reduce their impact. Its aim is to assist the formulation of policies, by offering sound scientific evidence on environmental science, that will lead to a more inhabitable and sustainable world for the generations to come.
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