Consideration of meteorological factors when calculating large canals

Conclusions The effect of meteorological factors on the dynamics of open-channel flows is taken into account, as a rule, when studying unsteady fluid flows [8–12]. In shallow-water equations (in particular, in the St. Venant equations), which are the most common mathematical model used for calculating open-channel unsteady flow, meteorlogical factors are included as conditions on the free surface (normal and shear stresses). The use of the indicated dynamic equations (of shallow water) makes it possible to obtain quite diverse information about the results of the effect of the atmosphere on the structure of the open-channel flow. The approach presented in this article, based on the equation of balance of mechanical energy and ultimately on the Bernoulli equation, does not permit obtaining such detailed information about the interaction of meteorological and hydraulic factors. It permits mainly obtaining simple estimates by means of which one can establish when the effect of meteorological factors on the hydraulic characteristics of flows in canals should be taken into consideration.Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 1, pp. 33–36, January, 1988.     

平原区截渗排水渗流计算方法的研究与探讨

描述了非完整沟(管)工程布设形式和补给出流条件,对现行的平原区截渗排水渗流计算方法进行了综合分析,针对单、双沟的对称和非对称布设形式,提出了系列的有限含水层厚度条件下,对称与非对称单、双沟截渗排水的渗流水动力学计算公式。计算结果表明,在补给和出流条件基本相同的情况下,双沟比单沟截取地下水量和降低地下水位的作用都明显增大。     

Calculation of the kinematic characteristics of uniform flow in canals

Conclusion The determinate method of calculating the correction factors in models of turbulence constructed on the basis of simulating the process of self-organization of a steady kinematic structure does not depend on the flow regime and, consequently, is in essence a new variational principle of continuum mechanics, the practical significance of which consists in that by means of it it is possible to solve precisely those problems which are not solved with the use of traditional variational principles.Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 5, pp. 31–35, May, 1988.     

戽流跃后临界水深计算方法的应用

本文针对戽流消能工的特点,考虑不同的戽流消能工的结构形式,推导了形成戽流消能所需的跃后临界水深计算公式。对所推导的公式,结合具体的工程实例与试验结果进行了对比计算,其结果说明计算公式可以应用于实际工程。     

Scale analysis of turbulent channel flow with varying pressure gradient简

In this paper orthogonal wavelet transformations are applied to decompose experimental velocity signals in fully develo-ped channel flows with varying pressure gradient into scales. We analyze the time series from turbulent data, to obtain the statistical characteristics, correlations between the adjacent scales and the principal scale of coherent structures in different scales by wavelet transformations. The results show that, in the counter gradient transport （CGT） region, skewness factors and flatness factors deviate strongly from the corresponding values of Gaussian distribution on certain scales. PDFs on each scale confirm this observation. Scale-scale correlations show further that the fluctuations on some certain special scales are more intermittent than nearby. Principal scale of coherent structure is coincident with the scales on which the statistical properties depart from Gaussian distribution. These features are the same for different families of wavelets, and it also shows some different features in the region between favorable pressure gradient and adverse pressure gradient.     

水平分支管路中油水两相流动研究

该文研究了两种直径的直管油水两相流动对流型和相含率的影响和在不同管径的水平并行分支管路中的相含率变化规律.实验设备包括内径为50 mm的水平主管道和内径为25 mm的分支管路.得到了不同入口条件下实验管段的流型和相含率图.实验指出:管道的尺度变化对于流型的影响较小,但对于油水两相的相含率和速度滑移有显著的作用.当油水两相流在并行分支管路中同时流动时,随着入口处水的表观流速增大,并行主管的截面油含率与并行分支管的差距逐渐缩小.     

月牙肋岔管水流数值模拟研究

随着电力需求的不断增长,抽水蓄能电站的建设日益受到重视,其调峰平谷功能成为电力系统不可缺少的重要组成部分.结合江苏某抽水蓄能电站岔管部分的设计要求,对带有月牙肋板的岔管水流进行模拟研究,采用SIMPLE方法进行迭代计算,通过求解三维κ-ε紊流方程,较好地模拟了水流的流速场,并且通过物理模型试验得到了验证,从而肯定了数值模拟的合理性.     

太子河流域河道内生态需水分区估算研究

本文基于生态水文学原理,结合流域三生用水格局以及污染源分布格局和污染物排放强度格局,以流域内水生态系统及其影响因素为研究对象,运用GIS技术,对太子河干流水体及其周围陆地所在的空间单元进行分类与整合,生成了11个太子河流域生态需水估算分区,分区内具有相对一致的生态需水特性;在分区的基础上,结195合6—太2子00河8干年流以水及生19态56特—征19,73通年过两水个文实系测列流分量析系,列选,择采小用市水、文本学溪法、对葠观窝音、阁辽水阳库、以小下林的子7个和分唐区马进寨行6个了水逐文月河站道内生态需水估算,估算结果显示了近天然水文情势的生态水量过程变化,有助于太子河干流水环境改善以及水生态恢复;估算的各站年生态需水量占年径流量的30%左右,能够在不影响现有水资源利用格局的前提下,通过合理的水资源优化配置,实现生态需水要求。     

轮灌渠道设计流量计算方法的一点思考

通过自上而下分配末级续灌渠道的田间净流量,再自下而上逐级推算各级轮灌渠道设计流量的计算方法,分别推定利用灌区设计灌水率和该渠道灌溉面积计算该轮灌渠道设计流量的计算公式,给相关规范中的相关计算公式予以复核明确,以利于设计工作快速有效地开展。     

复式河槽流量计算方法比较与分析

复式河槽在洪水漫滩后,直接运用曼宁方程计算过流能力将带来很大误差。本文系统地总结了复式河槽流量计算的各种方法,运用这些方法分别计算整个复式断面的流量和滩槽流量分配,并与英国科学工程研究协会洪水水槽设施 (SERC-FCF)的大量的系列水槽实验成果进行比较。通过比较发现：计算流量时,断面垂直分割法、单一河槽法和等速剖分法误差都很大;而其它方法精度都比较高。运用流量计算精度比较高的方法同时计算流量分配发现：对某一具体断面形态而言,很难准确说哪种方法的精度最高。通过对各种方法的综合分析,建议在计算天然复式河槽过流能力时,采用河槽协同度方法。     

辽河下游平原区河渠附近地下水非稳定流计算

河渠水量的失衡和地下水位的大幅度变化,必然会给水资源开发利用、合理保护,制定预案带来困难。因此随时掌握河渠附近地下水的非稳定变化,实时进行分析计算,对于合理的水资源调度,以及保护工农业生产和人民生活具有广泛的实际意义。     

平原灌区末级渠道量水试验研究

平原灌区末级渠道具有流量小、流量变化频繁、变幅大、多泥沙、多杂质、坡降缓的特点,要求量水建筑物水头损失小、抗淤积能力强。为了掌握流量过程,以便对灌区用水进行科学管理,必须开发和推广易于自动监控的先进量水设施。鉴于此,在河套灌区沙壕渠试验站建造了机翼形量水槽并对现有的文丘利量水槽进行试验,试验结果表明：两种量水槽基本符合平原灌区末级渠道的量水要求。     

黄河下游灌渠水流泥沙数学模型

本文结合灌渠的结构特点及水流泥沙特性，对一维非耦合，非均匀、不平衡沙基本方程组进行了合理的简化，根据实体模型试验实测资料，确定了自流与提灌时干，支渠分流的不同分沙分水比。