水电站尾水管出口流动特性数值模拟

本文应用三维有限体积法和ＳＩＭＰＬＥ－Ｃ算法，对古田溪水电厂尾水管和下游尾水洞进行了数值模拟。应用固液两相流理论，推导了具有不规则边界时的控制方程。在规划的矩形网格中，采用通度系数法处理计算区域的不规则边界问题。计算结果给出了尾水管出口处的流动规律，为古田溪电厂的现场实验提供了依据。     

三维水流数值模拟

本文针对三维水流特性，引入通度概念处理不规则计算边界，用ＶＯＦ法追踪自由表面，采用修正的Ｋ－ε模型封闭Ｒｅｙｎｏｌｄｓ方程，分别计算了溢流坝水流及消力池中水跃．计算结果较好地与实验结果符合．     

高水头电站岔管过渡段水力优化研究

高水头电站岔管处的水流流动较一般水头更为复杂,所产生的局部损失较大。为此,以高水头电站岔管过渡段的优化为研究对象,建立了不同岔管过渡段的三维数值计算模型,数值模拟了最大发电流量下不同锥角角度过渡管的岔管内流速和压力分布,分析计算了不同工况下的水头损失系数大小。结果表明:随着锥形过渡管锥角角度的增大,岔管处的回流区和相对低压区有效减小,局部损失系数也相对减小,流场分布更加均匀。     

不同液舱结构形式对晃荡的影响分析

本文就不同液舱结构形式对晃荡所产生的影响进行了分析研究。根据晃荡问题的特点及其液舱结构形式，建辛了数学模型。采用有限差分法离散流体运动方程，VOF法追踪自由表面，通度系数概念处理液舱内的障碍物。最后通过编制的计算程序，计算分析了不同结构形式液舱的防晃效果。     

用三维计算流体力学方法计算调压室阻抗系数

为了研究计算流体动力学方法确定阻抗式调压井阻抗系数的可行性，本文选用适合调压室流动的可行化k-ε湍流模型及考虑边壁粗糙度的壁函数，用二阶精度算法对T形岔管、管内孔口、突扩管和阻抗式调压室的流场进行了数值模拟。经比较发现采用计算流体动力学方法计算所得的结果在水头损失方面可达到与常规模型试验结果同等的精度，表明计算流体动力学可以应用于调压室的设计计算中。     

建筑物密集城区溃堤水流二维数值模拟

本文对建筑物高度密集的城区溃堤洪水进行了数值模拟。模型采用有限体积法对二维浅水方程进行了非结构离散，以Roe格式的近似Riemann解为基础计算界面通量。为考虑社区和楼房的容水性能引入了侵入系数的概念，采用物理模型试验结果验证了该数学模型的准确性和稳定性。应用该模型对哈尔滨市未来可能发生的溃堤洪水进行了模拟，研究表明，以二维路网为主要计算区域时，网格尺寸的大小对计算结果影响并不明显，而不同的侵入系数则对其影响较大。     

非正交网格有限体积法在三维潮流场计算中的应用

有限体积法是求解流体问题的一个非常有效的数值方法，本文研究非正交网络有限体积法在三维潮流场数值模拟中的应用。由三维浅水方程出发，利用有限体积法的积分模式并引入Ｇｒｅｅｎ－Ｇａｕｓｓ公式，将控制体单元的体积分转化为面积分，采用一种任意六面体单元，垂直涡动粘性系数定义为水深的函数，使之能适应复杂海哉和地形，又可获得不同水深的计算数据。     

溢流坝坝面水流数值模拟及其验证

采用修正的Ｋ－ε模型封闭Ｒｅｙｎｏｌｄｓ方程作为紊流控制方程，引入通度概念处理不规则边界，引用ＶＯＦ法追踪自由表面，对溢流坝坝面水流进行数值模拟。模型试验验证结果表明，采用本文建立的数学模型对溢流坝水流进行数值模拟是可行的。     

建筑物密集城区溃堤水流二维数值模拟

通过考虑社区和楼房内部的容水性,引入侵入水量的概念,建立了能够模拟建筑物密集城区溃堤水流运动的数学模型。该模型采用有限体积法对浅水方程进行非结构离散,通过Roe格式计算界面数值通量,给出了侵入水量的合理估算方法。通过物理模型的试验结果验证了本文模型的准确性和稳定性。最后应用该模型对哈尔滨市可能发生的溃堤洪水进行模拟,计算结果表明,该模型能较好地模拟溃堤洪水在城区内的运动过程,侵入系数的变化对计算结果有比较明显的影响。     

三维紊流数值研究

本文针对复杂三维水流所具有规则边界、自由表面及各向异性，引入通度概念处理不规则计算边界，用ＶＯＦ法追踪自由表面，采用修正的ｋ－ε模型封闭Ｒｅｙｎｏｌｄｓ方程，分别计算了实用重力坝及其下游戽式消力池中水流流场和一个三维水跃流场。计算结果较好地与实验结果符合。     

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.     

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.     

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.     

Serial discontinuities in a Rocky mountain river. II. Distribution and abundance of trichoptera

River regulation in the headwaters and middle reaches of the Gunnison River, Colorado, significantly altered distributions and abundances of Trichoptera fauna. Twenty-five species were collected from mainstream samples, with the greatest species richness occurring at an unregulated, rhithron segment above the central reach dams. At sites immediately below the three hypolimnial-release dams and a reregulation dam, species richness was reduced 35–90 per cent and abundance > 95 per cent. Net-spinning caddisflies were the dominant trichopterans at unregulated sites; Arctopsyche grandis in the upper reaches (218 organisms, 586 mg dry mass m^?2) and Hydropsyche cockerelli, H. occidentalis and Cheumatopsyche pettiti in the lower river (9041 total organisms, 6621 mg m^?2), downstream from the last dam. The observed distributional pattern of low trichopteran densities in dam tailwaters and high hydropsychid densities at sites 60–80 km below the central reach dams is a classic expression of continuum resets and adjustments in response to stream regulation as predicted by the Serial Discontinuity Concept.     

Surveying for Water Resources

Abstract

A professional Land Surveyor (Geomatician) describes the Hydrogeologists' survey requirements of a major water resources assessment for the government of The Sultanate of Oman (1992 to 1996). The need for objective specifications is stated. Specialist terms like geoid, spheroid, Mean Sea Level are explained and how to relate spheroidal levels to the geoid. Methods like traditional survey, satellite survey, and photogrammetry are introduced. The paper encourages coordinated working for the benefit of water resource assessment and recommends employment of the professional land surveyor for major studies.     

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.     

The Impact of Economic Development on Water Pollution: Trends and Policy Actions in Malaysia

The paper examines the impact of development activities on water pollution in Malaysia. Hence, the main objective of this paper is not just to examine the trends of development-induced water pollution around the region of the country but to know where the problems are and the policy measures taken by the government. It evaluates the probable causative relationship between problems introduced due to technology employed in water pollution control and governmental policy measures. It examines the relationship between development indicators as sources of pollution and polluted rivers over a period of 12 years. The findings of the paper have shown that despite the policy enforcement actions against the identified sources of water pollution, all the three development indicators (chosen based on those identified sources) still accounted for high percentage of river pollution in Malaysia. The findings of the paper were used to identify the central fact of the location of the problem. Some crucial conclusions of where the problems likely to be, as reflected in the findings, are: (a) the issue of interactive-effects between pollutants that many policy-makers are not aware of. This is when policy measures concentrate only on one source of water pollution; (b) the enforcement strength and/or effectiveness of policy measures themselves; (c) financial constraints to invest in appropriate technology especially sewerage systems for controlling human source of water pollution in the country; as well as those confronting small polluting industries (d) finally, lack of cooperation between government and private business firms to comply with regulatory policies for water pollution control.     

浅淡溢洪道改扩建方案与选择

溢洪道改扩建和进行溢洪道方案布置，要择优选取溢洪道进口型式、防冲消能工，以使其工程量省、施工快、运行管理方便     

Intangible Flood Damage Quantification

Flooding is a natural disaster that may cause tremendous tangibleand intangible damage to the national economy. The tangible damage assessment, i.e. the monetary value of all direct and indirect physical damages, has already been studied, whileintangible damages have not yet been taken into account. Thisarticle, therefore, is the first systematic attempt to assess bothtangible and intangible damages. The new proposed Anxiety-Productivity and Income Interrelationgship Approach (API) has been developed to quantify the intangible damage in monetary terms. The Bangkok area has been selected as the research area because several severe flood events have occurredthere over the last two decades. The 1983 Bangkok flood caused 6600 million baht in damage, according to estimates by the National Statistical Office (NSO). This article examines the totalflood damage (including the intangible damage) at different flood magnitudes. Case studies with and without flood mitigation projects are studied and compared. Furthermore, thisarticle also discusses the improvements over the conventional approach offered by the new API methodology.