顶管施工中新型聚合物添加剂对润滑减阻浆液性能的影响

本文选取聚丙烯酰胺、羟甲基淀粉、羟甲基纤维素、瓜尔胶、黄原胶和N-二甲基丙烯酰胺共聚物共6种聚合物,作为顶管施工润滑减阻浆液添加剂,通过对比和分析加入不同聚合物添加剂的浆液体系性能参数,得出以上六种聚合物适合用作顶管施工润滑减阻浆液添加剂的是羟甲基纤维素、黄原胶和N-二甲基丙烯酰胺共聚物。在此基础上,再通过调节加入浆液体系添加剂的掺量来研究其掺量变化对浆液性能产生的影响,得到最为适宜作为顶管施工润滑减阻浆液添加剂的聚合物是N-二甲基丙烯酰胺共聚物的结论。     

高聚物在明渠水流中减阻的实验研究

本文探讨了高聚物用于明渠流减阻的基本规律.研究说明,国产高聚物聚丙烯酰胺(PAM)具有显著的减阻效果,减阻百分比E随溶液浓度、渠道底坡及水力半径的增大而增大. 明渠水流减阻,可以增大泄量,从而达到减小排水构筑物尺寸,削减工程投资的目的.应用减阻技术,除了可用于增大水库泄放,城市泄洪以及污水排放的作用外,还可作为超设计标准特殊防护的一种措施.因此,本研究对发展高聚物减阻理论和推动该技术在工程技术中的应用是有积极意义的.     

表面活性剂减阻流体热边界层温度脉动及传热特性实验研究

该文针对在水中添加阳离子表面活性剂产生的减阻作用同时降低传热性能的现象,应用相位多普勒激光测量系统和热电偶温度测量系统对二维流道内表面活性剂减阻流体热边界层内的湍流温度脉动以及传热特性进行了实验研究.研究表明,表面活性剂减阻流体平均温度梯度在流动缓冲层很大,热扩散率较低,而水的热阻主要发生在近壁区域的高扩散层.表面活性剂减阻流体温度脉动强度与速度脉动强度有相似的分布趋势,其峰值都向外层移动.在近壁处的高扩散层温度脉动频率很小,而在平均温度梯度很大的低扩散层,减阻流体的温度脉动频率有所增强.而水的温度脉动频率比表面活性剂溶液高且在整个断面上几乎没有变化.对于表面活性剂热流体,湍流温度脉动对轴向热流量的贡献更大,使得轴向热流量的最大值出现在靠近温度脉动强度最大值所在的位置.表面活性剂减阻流体法向湍流热流量分布与雷诺应力分布有相似的趋势.     

肋条减阻

随着世界上能源消耗的不断上升，使人们不得不认真考虑如何有效的保护有限的能源，探求节约能源的新技术和新方法。湍流减阻就是在这种应用背景下提出在新课。经过二十多年的努力，特别是湍流理论的发展，使得湍流减阻理论和应用得到了突破性的进展。就减阻技术讲，有肋条减阻、聚合物减阻、大涡硫碎减阻、吹气和吸气减阻、微气泡减阻等，这些减阻技术一个共贩考虑，就是要控制边界层内的湍流结构，特别是拟序结构，减少湍能的耗损以     

黄河下游洪峰增值研究综述

该文综合介绍了近几年黄河下游调水调沙期间出现的洪峰异常增值现象及其发生的水动力学机理、概念验证及与其紧密相关的极细沙减阻和水槽试验研究成果,并介绍了黄河水利科学研究院利用“多沙河流洪水演进与冲淤演变数学模型”对洪峰增值实际过程的验证及预报情况等.对于泥沙减阻力学及减阻效应方面的研究任重而道远,该文旨在抛砖引玉,借此希望更多的学者能够关注这一问题的研究.     

重力场下平板边界层内气液两相流动数值分析

通气减阻技术因具有降低能耗和环境污染小等效果,在工程领域内得到广泛关注。为研究重力场中气相在平板湍流边界层内流动演化过程及由此产生的减阻效应,该文耦合连续表面张力(CSF)的VOF多相流模型和标准k-?湍流模型,求解非定常RANS方程,对边界层内气液两相流动进行数值模拟。通过计算结果与实验结果的对比,验证了数值方法的有效性;进而对不同通气流量和来流雷诺数下,气泡当量直径、近壁区空隙率及流动减阻率进行定量分析。结果表明:减阻效应与近壁区空隙率密切相关;来流雷诺数和通气量的提高,均能增强减阻效应。     

非牛顿流体在圆管中分层流动及减阻规律

本文提出了研究圆管分层流动的新模型，并利用该模型研究了非牛顿流体在圆管中分层层流流动，得出了速度场的解析分布式，最后，研究了分层流动的阻力规律，为分层掺气减阻提供了理论依据。研究表明，分层掺气可以在较大范围内实现有效的减阻。     

添加网格对增强表面活性剂减阻流体传热性能的试验研究

本文应用热电偶测温系统和PIV（Particle Image Velocimetry），激光测量系统对二维流道内添加网格后CTAC（Cetyltrimethyl Ammonium Chloride）表面活性剂减阻流体的传热性能和流动结构进行试验研究。研究表明：在完全减阻区内，减阻流体的传热性能大幅度降低；当雷诺数超过临界雷诺数后，传热性能呈指数级快速增长；网格的添加破坏了表面活性剂的胶束网状结构，在一定程度上恢复了流场的湍流强度，从而使传热效果显著增强。     

黏性泥石流残留层的床面减阻研究综述

黏性泥石流运动理论的核心问题在于确定黏性泥石流运动阻力和流速。但由于其运动的复杂、流态的多样,导致了阻力准确计算的困难,也制约了泥石流运动流速和流量公式的建立和推广应用。关于黏性泥石流的运动阻力问题,目前多聚焦于泥石流固液间相互作用的内部阻力关系,鲜见对于其床面阻力的研究。介绍了黏性泥石流的典型运动过程—"铺床",描述了铺床过程形成的残留层导致床面减阻现象,概述了目前国内外各泥石流运动模型对泥石流阻力的研究,并总结了残留层导致减阻的可能原因和目前多采用的床面阻力计算方法。认为残留层导致的复杂减阻效应,是黏性泥石流运动尤其是高速运动研究中不可忽视的一部分,但目前各类模型和水力学经验公式都无法概化黏性泥石流运动床面的阻力变化。鉴于此,提出了未来可开展的工作:(1)认知"铺床"导致的残留层的形成和发展过程;(2)探讨残留层床面减阻机制;(3)研究残留层床面阻力计算。     

圆管中分层层流流动的新模型及减阻规律

本文提出了研究圆管分层层流流动的新模型，并利用该模型研究了圆管分层流动速度分布规律，得出了速度场解析表达式，最后，研究了分层流动的阻力规律，为分层掺气减阻提供了理论依据．算例表明，分层掺气可以实现有效的减阻     

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.