解极近水面飞行时全机气动力中水波效应的边界元法

本文以边界元法为基础，在线性水波的假定下，对贴近水面飞行的三维飞行器，提出了一种计算气动力中水波效应的方法。本文共分三部分：I．分析了用边界元法计算非定常压力分布的困难和产生这一困难的原因，指出了对非定常问题，强度分布函数解必须保证唯一性而不能差一个随时间变化的常数。为此对无穷远条件必须有一个正确提法，并在此基础上给出了克服这一困难的方法。Ⅱ．水波效应问题的数学提法，包括各种定解条件和解的最后边界积分形式，导出了在飞行器形成的压力场的作用下波高应满足的微分积分方程，给出了求解的基本方法和步骤。Ⅲ．对于一个包含有复杂外形的机身、机翼、端板、垂尾和平尾的三维机型在贴近水面飞行时，作了包括水波效应在内的全机气动力计算，给出了水波效应随攻角、飞行高度、波幅、波长及波的入射方向等的变化，得到了有意义的结果，同时也证明了本文提出的计算非定常涡强分布函数的方法是正确的。     

挡土结构中土体被动临界滑动场及被动土压力的数值计算

本文将边坡临界滑动场方法进行推广和改进，计算挡土结构中土体被动临界滑动场PCSF和被动土压力。首先建立土体极限平衡方程并引入条间力函数，给出平衡方程求解格式；介绍改进的土体临界滑动场数值模拟技术；最后给出实用的被动土压力计算图。本文方法原理简单、精度高，可应用于工程计算。     

随机脉动水压力作用下的结构响应

本文从分析相关系数与相干函数的相似性出发，讨论了结构对连续分布的脉动压力作用的随机响应，给出了相干函数表达的结构响应，并定义了新的时空相关尺度－相干尺度，这个尺度实际上是每个频率分量随机荷重的平均作用空间，最后给出实例对比了试验与计算结果，说明提出了方法是正确的。     

三维频域有航速格林函数的数值计算与分析

Havelock型三维移动脉动源格林函数的计算是面元法求解航行船舶在波浪中的运动问题的关键.该文基于单重积分形式的移动脉动源格林函数,采用LOBATTO法以消除积分区间端点处的奇异性,采用多项式法快速准确计算复指数积分,在格林函数的偏导数积分计算中对复指数积分项进行了分部积分处理,解决了格林函数在π/2处被积函数趋于无穷且出现高频振荡所导致的积分困难.数值计算和比较表明:该方法可以准确计算出不同航速和脉动频率下任意位置的格林函数及其偏导数,能准确给出不同速度下三维移动脉动源的波形,适合用于有航速浮体的频域水动力计算中.     

三维振荡水柱波能转换装置的流体动力计算

文章对三维有侧向开口的波能转换固定式箱体;受波浪扰动时,用三维GREEN函数法计算箱体内振荡水柱的流体动力特性。在计算中使内场的响应脉动源与外场的扰动脉动源,两者在交界面上相互匹配,以满足压力与速度连续条件。计算在HP-1000型机进行,结果和模型试验比较,相当一致。     

数值计算域内产生波浪的方法

解决入射边界域内反射波浪吸收问题的方法之一是在域内产生所需的波浪，而在边界处采用其它方法来吸收域内反射波浪，本文采用源函数的方法。给出了Bossinesq方程计算域内产生波浪的方法，典型波浪的数值模拟计算结果表明，该方法可以在域内生产所期望的波浪。     

浅水波-流对直立桩柱作用的分层数值解法

本文采用分层方式，用水气比拟方程计算由于存在桥墩等障碍物而造成的浅水波高度的变化，以此给出水下粘性层内计算域上表面的压力，用传统的N-S方程计算粘性层内的流动，得到了波一流联合作用下桥墩上的压力分布和河床上压力与剪应力分布随时间周期性的变化过程，并得到了一些有意义的结论。     

三峡原型水轮机的非定常湍流计算和压力脉动分析

本文对三峡原型混流式水轮机进行了三维非定常湍流计算，得到水轮机的非定常流场，预测了尾水管内、转轮前、活动导叶前、固定导叶前和蜗壳进口的压力脉动。通过与模型试验预测结果的比较看出，计算能够准确预测水轮机内的压力脉动。分析表明尾水管内涡带和转轮与活动导叶间的动静干扰是产生压力脉动的两个主要脉动源，并在整个水轮机流道内传播。     

任意形状复合油藏压力动态的边界元分析

油气藏形状对井底压力动态响应有着显著的影响，常规的解析方法只能计算规则形状油气藏的井底压力响应。该文建立了任意形状复合油藏不稳定渗流的数学模型，并将区域分割法与边界元方法相结合，研究了任意形状复合油藏不稳定压力响应的计算方法，应用杜哈美原理考虑了表皮效应与井储系数对井底压力动态响应的影响。绘制并分析了复合油藏的典型曲线，通过分析指出油藏的边界性质会影响典型曲线后期形态，而内区形状的也可能掩盖复合油藏典型曲线的特点。     

对悬移质含沙分布Rouse公式沿垂线积分的研究

文中着重研究了悬移质泥沙分布Ｒｏｕｓｅ公式沿垂线的积分问题，给出了悬移质垂线平均含沙量与底部含沙量的比值函数，并给出了此函数的计算方法。     

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. I. Distribution and abundance of plecoptera

Samples were taken year-round at eleven sites along the altitudinal profile (2900-1400 m a.s.l.) of the Gunnison River, a 329 km tributary of the Colorado River, to document the distribution of the Plecoptera and to evaluate responses to hypolimnial-release dams in the headwaters and middle reaches. Twenty-two species were present, with the greatest species richness occurring in an unregulated segment upstream of the middle reach dams; average nymphal biomass over the study period (175 organisms, 395 mg dry mass m^?2) was also greatest in this segment. Only four species (58 organisms, 48 mg m^?2) were present in the tailwaters of the headwater dam and values were greatly reduced (nine species; 35 organisms, 180 mg m^?2) below the middle reach dams. The stonefly community recovered ca. 80 km downstream from the last dam (15 species; 244 organisms, 250 mg m^?2), apparently in response to natural resetting of environmental conditions corresponding to those above the middle reach dams. At the most downstream site (11) only four species (four organisms, 16 mg m^?2) were present. The observed distributional pattern is a classic serial discontinuity in response to hypolimnial stream regulation in a temperate latitude river.     

地下厂房施工过程的三维非线性数值模拟分析

根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。     

Impacts of Microcystis on algal biodiversity and use of new technology to remove Microcystis and dissolved nutrients

Cyanobacteria often dominate eutrophic lakes, outcompeting green algae that are required by fish and zooplankton. This study was undertaken to ascertain the impact of the cyanobacterium, Microcystis, on algal biodiversity. Under laboratory conditions, we found that the presence of Microcystis decreased phyla richness by 58%, phyla evenness by 47%, genera richness by 66% and genera evenness by 51%. Analysis by mixed anova s demonstrated a significant interaction between treatment and time and confirmed a significant reduction in richness and evenness of phyla and genera. We also conducted a phosphate restriction assay on the algae in Mason Lake (Irvine, CA, USA) and found that the threshold needed for algal growth there was 0.02 mg L^?1 PO₄. A pilot study was then conducted to test the effectiveness of the Blue Pro? water treatment facility in removal of this colonial organism from Mason Lake, in addition to removal of dissolved nutrients required for its growth. We measured a 97% reduction in Microcystis cells, a 72% reduction in chlorophyll‐a, and a 96% reduction in phosphate after just one 10 min cycle through the unit. Our study demonstrated that removal of Microcystis colonies may allow green algae to increase in numbers. This may improve algal biodiversity, which will benefit zooplankton and fishes.     

Evaluation of freshwater mussel relocation as a conservation and management strategy

The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.     

基于模型试验的河床砂砾石层基本特性研究

为了经济可靠地确定深厚覆盖层的基本特性参数,以大渡河双江口水电站坝基河床砂砾石层基本特性研究为工程背景,进行大尺寸模型试验,研究河床砂砾石层的旁压模量和动探击数随密度、级配以及上覆压力的变化规律。根据室内模型试验结果,结合现场旁压试验及钻孔试验成果,推断出坝址区河床砂砾石相关层位的密度,并依此进行砂砾石室内力学试验,获得设计所需力学参数。研究成果可为深厚覆盖层基本特性测试提供新的方法。     

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.     

簸箕李引黄灌区水沙分布及优化调度的经验

灌区利用水沙观测所取得的资料和试验数据，运用水沙运动力学理论，总结分析和揭示了灌区水沙分布的规律和特点。在此基础上，结合灌区的实际运行情况，围绕减少骨干渠道的淤积进行探讨、研究，进而，优化水沙调度方案。该方案实施后，骨干渠道减旅伴效果明显，取得了成功的经验。     

小湾水库大坝防渗面板及其裂缝的加固处理

小湾水库大坝防渗面板整体抗渗性能差,且存在多条裂缝,通过对面板钢丝网喷涂丙乳砂浆加固处理及其裂缝修补,大坝渗漏量明显减少,且左岸上灌浆廊道内及大坝下游坝面92～93 m高程下廊道入口处原有小股射流全部消失.     

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.