姬昌辉 谢瑞 张幸农 申霞

摘 要：生态河道中的植物在净化水质的同时增大了河道阻力，是抬高河道水位、影响河道行洪安全的原因之一。采用塑料草模拟植被，建立横断面为梯形的明渠水槽，研究植被淹没情况下明渠水深、流速以及植物间距对明渠切应力的影响。通过对研究水体的受力分析，推导出床面平均切应力计算公式;根据试验结果，计算得出不同条件下的边界平均切应力，分析不同水流条件、不同植物密度情况下明渠边界切应力的变化规律。结果表明：水流流速以及植物布置间距对明渠边界切应力影响较大，水深对边界切应力影响相对较小。

关键词：明渠;淹没植被;切应力;流速

中图分类号：TV133 文献标志码：A

doi：10.3969/j.issn.1000-1379.2021.05.013

Abstract： The plants in the river not only purify the water quality， but also increase the resistance of the river and raise the water level. Therefore， the resistance of river with plants is one of the current research hot spots. Plastic grass was used to simulate vegetation， and an open channel with trapezoid cross section was built to study the influence of water depth， velocity and plant spacing to the resistance of open channel with submerged vegetation in this paper. Through the force analysis of the research water body， the calculation formula of the average shear stress of the bed surface was derived. According to the test results， the average shear stress of the boundary under different conditions was calculated and the change rule of the shear stress of the open channel under different flow conditions and different plant densities was analyzed. The results show that the flow velocity and plant spacing have a great influence to the boundary shear stress， while the water depth has a relatively smaller influence to the boundary shear stress.

Key words： open channel; submerged vegetation; shear stress; velocity

植被在河道生态修复中起着重要作用，在净化河道水质、为水生动植物提供栖息地的同时，植被也增大了河道水流阻力，抬高了河道水位[1]。含植物河道的阻力研究近年来受到国内外专家的关注。唐洪武等[2]依据等效阻力作用原理，建立了含植物河道等效综合Manning 系数的计算公式。Nezu等[3]采用圆柱棒模拟刚性植物，指出雷诺应力达到最大值的位置位于植物顶端，给出了植物层上部雷诺应力分布公式。Cheng等[4]通过对比管流和植被明渠流，用与植被有关的水力半径重新定义了雷诺数，提出了一个新的含有雷诺数的摩擦力函数。王雯等[5]采用标准k-ε紊流计算模型，通过三维数值计算对双层淹没刚性植被水流特征进行研究，给出了基于时间空间双平均条件的紊动能、雷诺应力、紊动耗散率分布状况，指出在每一层植被顶端都会出现一个明显的峰值。……