河渠水面线推求方向的可行性研究  

Feasibility study on the computational direction of flow profile of river and channel

作　　者：刘曾美[1] 吴俊校[2] 陈明[2] 

机构地区：[1]华南理工大学水利水电工程系,广东广州510640 [2]广东省水利水电建设管理中心,广东广州510600

出　　处：《水利水运工程学报》2011年第1期76-83,共8页Hydro-Science and Engineering

基　　金：广东省防洪减灾研究项目

摘　　要：河渠水面线的推求,首先必须确定推求方向,因为虽然从理论上可从上游或下游断面开始递推,但实际上都可能遇到无法推求的情况.构建的规则河渠水面线推求方向可行性分析方法,首先分析水面线计算式上、下断面能量函数曲线的特性,研究计算河段长度、河道底坡对其的影响;然后探讨上、下断面的能量函数曲线相对位置关系,从而探究无法推求的原因及求解的规律性,并以实例进行分析.研究结果表明,由下游向上游推求等截面缓坡、临界坡河段及收缩河段,或由上游向下游推求等截面陡坡、临界坡河道及扩散河段,总能找到可行解或通过缩短计算河段长度找到可行解;而由上游往下游推求等截面缓坡河段、收缩河段,或由下游向上游推求等截面陡坡河段、扩散河段时,则存在无解区域,且无解区域发生在临界流态的某一邻域内,邻域左右半径不一定相等;此外,河段长度愈长,坡度愈陡,邻域半径愈大.The computational direction must be decided first in computation of water surface profile of river and channel.Theoretically,it can be obtained from either the upstream cross-section or the downstream cross-section of the calculated reach.However,in practice,when the calculation is carried out from either the upstream cross-section or the downstream cross-section,it may often be encountered that the results can not be reached.The method for analyzing the feasibility of computational direction of water surface profile for regular river and channel is established in this paper.First,it analyzes the characteristics of energy function curve of the upstream and downstream section in the formula of water level,and the influence exerted by the length of the calculated reach and the slope of river.Then the relative position of the energy function curves of the upstream and downstream section is researched.Consequently,the reason why the results can not be reached and the solution laws of water level calculation are researched.The research results show that：if the calculation of water surface curve is carried out from the downstream to the upstream of equal cross-section with a gentle or critical slope or the reach with the constricted cross-section,or is carried out from the upstream to the downstream for the river channel of equal cross-section with a steep or critical slope or the reach with the diffuse cross-section,it is possible to find out the feasible solution.If the calculation of water surface curve is carried out from the downstream to the upstream of equal cross-section with a steep slope or the reach with the diffuse cross-section,or is carried out from the upstream to the downstream for the river channel of equal cross-section with a gentle slope or the reach with the constricted cross-section,there is a non-solution region.Moreover,the non-solution region is around the critical flow,and the longer the length is or the more gentle the slope is,the larger the non-solution region is.

关 键 词：水面线 推求方向 可行性 能量函数曲线 

分 类 号：TV133[水利工程—水力学及河流动力学]