平面二维河床冲淤计算有限体积法

给出了边界层坐标系下平面二维河床冲淤计算数学模型方程 ,并用河势贴体正交曲线二维网格形式来划分计算区域 ,模型控制方程及定解条件采用有限体积法进行离散 ,数值求解基于SIMPLE算法。该模型用武汉河段天然实测资料进行了验证 ,并在工程实践中得到了大量的应用和检验     

两相流动中流固两相耦合阻力的数值估计

本文从纳维-斯托克司方程出发,用有限差分法计算粘性流体绕三维均匀正方排列无穷球点阵的流动,以图估计两相流动中颗粒体积率和颗粒雷诺数对颗粒阻力的影响。计算中使用了贴体坐标数值网格生成方法。计算结果和实验结果、经验公式作了比较。考虑到真实两相流动的复杂性及本文采用的力学模型的理想性,可以认为两者吻合较好。     

分岔管道三维湍流水力特性数值模拟

建立了分岔管道水动力学的计算模型,求解三维贴体坐标系下水流控制方程。计算中采用修正的k-ε湍流模型,应用有限体积法离散方程,物理变量采用同位网格布置,控制体表面上各变量的值用界面动量插值法计算,速度-压力耦合计算采用SIMPLEC算法。本文应用该数值模型模拟了三维弯道水流的水力特性,并与模型试验实测值进行了比较,结果吻合较好。最后应用该数值模型预测了35°分岔管道连接区域三种流动情况的水力特性。     

支流河口水沙运动的二维数学模型研究——以长江上游的嘉陵江河口为例

本文建立了一个支流河口水沙运动的二维数学模型．采用贴体正交曲线坐标克服了干支流汇合处河道边界形状复杂的困难，给出了正交曲线坐标系下二维全沙模型的基本方程及数值计算方法．以长江上游的嘉陵江河口为例，分析了支流河口河段水沙特性及浅滩成因，模拟了汇合口河段流场及泥沙冲淤分布，计算值与实例值吻合良好．为支流河口浅滩演变及整治研究提供了一种新的模拟方法．     

支流河口水沙运动的二维数学模型研究

本文建立了一个支流河口水沙运动的二维数学模型.采用贴体正交曲线坐标克服了干支流汇合处河道边界形状复杂的困难，给出了正交曲线坐标系下二维全沙模型的基本方程及数值计算方法.以长江上游的嘉陵江河口为例，分析了支流河口河段水沙特性及浅滩成因，模拟了汇合口河段流场及泥沙冲淤分布，计算值与实例值吻合良好.为支流河口浅滩演变及整治研究提供了一种新的模拟方法.     

河势贴体河道平面二维正交网格生成方法的研究及应用

基于河势概念和Hermite三次插值函数 ,提出了河势贴体河道平面二维正交四边形网格的生成方法 ;与边界层坐标系下水深平均流体力学控制方程和SIMPLER算法联合使用 ,建立了河道平面二维数学模型 ;进行了葛洲坝枢纽至磨盘溪河段二维网格生成及水流泥沙数学模型的实例研究 ;讨论了该网格生成方法的主要特征     

基于一种贴体曲线网格生成技术的研究及应用

阐述了网格生成在数值计算中的重要性，运用FORTRAN编程选取合适的调节函数，求解Possion方程得到了贴体曲线网格；分别对一天然河段划分贴体曲线网格和三角形网格进行计算，并与实际观测值进行了比较，表明了贴体曲线网格的优越性和可行性。     

河势贴体河道平面二维正交网格生成方法的研究及应用

 基于河势概念和Hermite三次插值函数,提出了河势贴体河道平面二维正交四边形网格的生成方法;与边界层坐标系下水深平均流体力学控制方程和SIMPLER算法联合使用,建立了河道平面二维数学模型;进行了葛洲坝枢纽至磨盘溪河段二维网格生成及水流泥沙数学模型的实例研究;讨论了该网格生成方法的主要特征。 关键词：正交网络;数学模型;河势;Hermite函数;边界层;SIMPLER算法     

稳封期天然河道冰塞堆积的数值模拟

冬季寒区河道中容易出现冰塞,冰塞出现使过水断面减少,河道阻力增加,进而引发凌洪灾害。借鉴泥沙输运理论推导得到的冰塞面变形方程,并结合标准k-ε模型建立了稳封期天然河道冰塞堆积厚度的数值模拟计算模型,采用贴体坐标变换法将曲线网格转化为正交网格,控制方程离散求解采用有限体积法,选取同位网格方法将所有计算变量布置于同一控制体积,引入动量插值法和压力校正方程耦合求解速度压力场,进而求解冰塞面变形方程获得冰塞堆积厚度。选取黄河河曲段天然河道,应用模型计算得出了稳封期河道中的冰塞堆积厚度,对比实测资料表明,数值模拟与实测结果比较一致,验证了该数学模型的实效性,表明冰塞面变形方程可应用于天然河道冰塞堆积厚度的数值模拟计算。     

水轮机导叶含端面间隙的水动力学研究

本文基于N－S方程和标准κ-ε紊流模型，采用贴体坐标和结构化网格，用SIMPLE算法，对带有间隙导叶叶栅进行三维不可压定常粘性流动数值模拟。详细研究比较了导叶有无间隙两种情况下的水轮机导叶水动力学特性，揭示了水轮机导叶端面间隙流动的运动规律以及间隙流动对主流的影响，计算结果与实验吻合，从而为导叶及上下端面的磨蚀以及水轮机的水力稳定性提供理论依据。     

Call for Papers

正As the eldest and most distributed professional journal of water industry,Water Wastewater Engineering(W WE)gained very wide acceptance from the colleagues working in this field in this country since start publication in 1964.Now it is administrated by the Ministry of Construction of the People’s Republic of China and sponsored by the China Civil Engineering Society etc.     

库水波动下库岸边坡地下水浸润线解析解及误差分析

解析法是库岸边坡地下水浸润线计算中便于实际应用的方法,但该方法须基于若干假定并对潜水运动基本方程线性化后才能求解。针对各假定和线性化过程建立不同的地下水渗流数学模型,用解析法和有限元法解答上述数学模型,分析各误差大小及其规律。结果表明：库岸垂直处理带来的误差要小于方程线性化处理和不考虑非饱和渗流带来的误差,而且它们都随渗透系数变大而减小;在三峡库区库水调度情况下,假定库水位等速变化带来的误差对大多岸坡而言可以忽略;计算库岸边坡地下水浸润线时,解析法只适用于水位变化幅度相比含水层厚度较小,且几何边界规则、岩土结构简单、岩土体渗透性较好时的情况。     

Changes in Summer Irrigated Crop Area and Water Use in Southeastern Turkey from 1993 to 2002: Implications for Current and Future Water Resources

Changes in summer irrigated cropland acreage and related water use are estimated from satellite remote sensing and ancillary data in semi-arid Southeastern Turkey where traditionally dry agricultural lands are being rapidly transformed into irrigated fields with the help of water from the Euphrates-Tigris Rivers. An image classification methodology based on thresholding of Landsat NDVI images from the peak summer period reveals that the total area of summer irrigated crops has increased three-fold (from 35,000 ha to over 100,000) in the Harran Plain between 1993 and 2002. Coupled analysis of annual irrigated crop area from remote sensing and potential evapotranspiration based estimates of irrigation water requirements for cotton indicate a corresponding increase in agricultural water use from about 370 million cubic meters to over one billion cubic meters, a volume in accordance with the state estimates. These estimates have important implications for understanding the rapid changes in current agricultural withdrawals in Southeastern Turkey and form a quantitative basis for exploring the changes in future water demands in the region. For example, expansion of irrigated lands have led to a steady decrease in potential evaporation due to increased roughness and decreased humidity deficit in the Harran Plain. Assuming that the changes in future evaporation conditions will be of similar nature, water use for irrigation is expected to decrease over 40 percent in future irrigation sites. Incorporating this decrease in overall planning of the irrigation projects currently under construction should lead to improved management, and by extension, sustainability of water resources in the region.     

SPATIAL AND TEMPORAL WATER QUALITY VARIABILITY IN AQUATIC HABITATS OF A CULTIVATED FLOODPLAIN

The floodplains of lowland rivers contain diverse aquatic habitats that provide valuable ecosystem services but are perturbed when intensively cultivated. Hydrologic, water chemistry and biological (fish) conditions in five aquatic habitats along the Coldwater River, Mississippi, were measured for more than 4 years: the river, two severed meanders that functioned as backwaters, a managed wetland and an ephemeral channel draining cultivated fields. Off‐channel habitats were connected to downstream regions 0.10% to 32% of the dry season and 24% to 67% of the wet season. The median temperatures for the five monitored sites ranged from 18°C to 23°C, the median total solids concentration for all sites was 135 mg L^?1, the median total phosphorus was 0.29 mg L^?1 and the median total nitrogen was 1.56 mg L^?1. Chemical and physical water quality displayed strong seasonal differences between the wet winter/spring and the dry summer/fall periods so that temporal variation consisted of gradual seasonal trends superimposed on strong diurnal variations. All off‐channel habitats exhibited periods of hypoxia and temperatures >30°C during the dry season. Between‐site gradients of water and habitat quality were strongly coupled to water depth and runoff loading. The rehabilitation of one backwater by increasing water depth and diverting agricultural runoff was associated with improved water quality and fish species richness relative to an adjacent untreated backwater. The diversion of polluted runoff and the use of water control structures to maintain greater water depth were observed to be effective management tools, but the former reduces the water supply to habitats that tend to dry up and the latter reduces connectivity. Published in 2011 by John Wiley & Sons, Ltd.     

Site modelling methods for detecting hydrologic alteration of flood frequency and flood duration in the floodplain below the carlyle dam,lower Kaskaskia River,Illinois, USA

Reports concerning the influence of dams on river hydrology vary among researchers, interest groups and government agencies. These often contradicting statements may occur because changes in hydrology caused by dams are distinct for each dam and river watershed. The objective of this research was to use site specific techniques to determine if the 1967 installation of the Carlyle Dam, lower Kaskaskia River, Illinois, altered flood frequency and duration within the forested floodplain located below the dam. Results indicated a decrease in flood duration and frequency, and a decrease in annual flood frequency variation at a site 6.4 km below the dam. Pre‐dam versus post‐dam differences in flood frequency and duration at the site 32.2 km below the dam were related to climate rather than dam effects. Although dam impacts are a concern, this research shows that distance downstream from the dam and downstream tributary and watershed characteristics should be considered before assuming that the dam has changed hydrologic parameters for portions of rivers. This research also indicates that areas of the lower Kaskaskia River may still maintain hydrologic ecological integrity, and could be targeted for restoration and adaptive management purposes. Hydrologic modelling combined with river gage and on‐site well measurement techniques presented in this study could provide detailed flood frequency and duration information for land use, sociological and geomorphological questions in focus areas within river floodplains. Copyright © 2008 John Wiley & Sons, Ltd.     

浅谈优化Vray渲染在制作三维场景的应用研究

用Vray三维渲染引擎来渲染三维场景,其质量和速度是由一些影响因素和参数设置决定的,不同的参数和因素,可以得出不同的三维渲染效果.因此,分析、优化三维渲染质量和速度的影响因素,正确、合理的选择参数对提高Vray最后渲染阶段的质量和速度非常重要.     

固结、渗流和沉积控制方程研究

本文从两相流体动力学的守恒方程出发，考虑固相、液相的相对运动，推导了可以考虑场的不均匀性和流体压缩性的统一形式的控制方程，并对方程所基于的物理概念和相互联系进行了必要的分析。通过对方程适当形式的表达，可导出用于大、小变形固结、渗流和沉积的简化方程，显示了在不同领域的三个理论存在一定的统一性。方程推导过程并未对本构关系加以限制，适用范围较广。依据实际问题的要求，作了不同形式的简化。     

四川省及重庆市中型水电站效益分析

该文分析了四川省及重庆市几座中型水电站的调查材料表明：四川省及重庆市中型水电站不仅在川渝主网和地方电网中起着很大的作用，并具有巨大的社会效益，同时还有综合利用效益，说明修建中型水电站的优越性．     

Spatio‐temporal variation of gross CO2 and CH4 diffusive emissions from Australian reservoirs and natural aquatic ecosystems,and estimation of net reservoir emissions

Carbon dioxide (CO₂) and methane (CH₄) diffusive emissions were measured during two field surveys in Queensland and Tasmania, Australia, using the floating chamber method. Bubbling and degassing emissions in 2010 were estimated in Koombooloomba Dam reservoir using only inverted funnels and gas concentrations, respectively. A total of 14 reservoirs and 16 rivers and lakes were sampled from 2006 to 2010. Spatial variation was substantial within each water body, as well as between them. The main drivers of diffusive emission variation were physiographic region and climate, with a clear demarcation being observed between diffusive emissions from tropical Queensland and temperate Tasmania, and between the humid West Coast Range (Tasmania) and dry Central Plateau (Tasmania). Higher CO₂ and CH₄ diffusive emissions were observed during the dry season, when long water residence times would promote organic matter degradation. Estimated total gross emissions, including diffusive, bubbling and degassing emissions, for Koombooloomba Dam reservoir were about 1.5 × 10⁶ t CO₂eq km² per year, or 24 × 10⁶ t CO₂eq per year. This corresponds to a plant emission factor of 3.18 kg CO₂eq MWh^?1. Using an estimate of terrestrial emissions derived from literature data for the Tully River catchment area, rough estimated net emissions from the catchment area are about 44 kt CO₂eq per year, or 5.83 kg CO₂eq MWh^?1, which is in the lower range of the studied reservoirs.     

掺MgO混凝土的宏细观试验研究

利用MgO膨胀剂的延迟微膨胀效应能显著提高大体积混凝土的力学性能,产生的预压应力还能有效提高大体积混凝土抵抗温度开裂的能力,但目前对其微观机理研究不多。采用宏观与微观相结合的方式,研究了不同活性指数、不同掺量的MgO混凝土的力学性能,利用SEM/EDS微观分析手段揭示了MgO对混凝土性能影响的作用机理。试验结果表明：MgO取代部分水泥掺入混凝土中,混凝土的力学性能降低;掺量为4%~5%时,活性指数为100s的MgO混凝土的膨胀率大于活性指数为50 s的MgO混凝土;MgO混凝土的膨胀特性与Ca,Si,Mg,Al等元素的分布情况有关,掺入的MgO将改变界面区Ca,Si,Mg元素的富集特性,Ca元素和Mg元素更易于在界面区富集,导致混凝土宏观力学性能的降低。