固—液两相流中的一种湍流模式

定义了体积分数速度，并由此建立了固－液两相流中的一种湍流模式，模化了动量方程，Ｋ方程及ε方程，本模型中，考虑了相间的速度滑移，颗粒间的作用及相间作用，对一管湍流中固－液混合物流动的预测表示与实验结果比较一致。     

固－液两相流中的一种湍流模式

定义了体积分数速度，并由此建立了固－液两相流中的一种湍流模式（Ｋ─ε双方程模式），模化了动量方程、Ｋ方程及ε方程。本模型中，考虑了相间的速度滑移，颗粒间的作用及相间作用，对一管湍流中固－液混合物流动的预测表示与实验结果比较一致。     

水涡轮机械中的湍流固—液两相流动及磨损研究

导出了固体颗粒在任意流场中运动的Ｌａｇｒａｎｇｉａｎ方程对此方程进行线性化，并求出了其颗粒运动方程的解析通解。使用颗粒运动方程数值求解和分析稀疏颗粒湍流场中固体颗粒的运动。建立了湍流固－液两相液的Ｋ－ε双方湍流模型，体积分数流模型，Ｅｕｎｌｅｒｉａｎ－Ｌａｇｒａｎｇｉａｎ混合湍流模型以及颗粒磨损模型，利用这些模型对一些水涡轮机械过流通道内的流动及固壁磨损进行了模拟，其预测结果与实验结果较为一致。     

稀薄气—固两相流中相间的相互作用模型

本文以稀薄气－固两相湍流流动为研究对象，推导并模化了考虑固体颗粒存在时，气相的湍流模型方程，在拉格郎日方法中实现了气－固两相间动量、湍动能的相互作用。尤其是提出当量密度及当量耗散系数两个概念后，使模型方程的型式等同于标准Ｋ－ε模型，很适合工程应用。而气相对粒子湍流扩散的影响则由类似于布朗粒子扩散的Ｍｏｎｔｅ Ｃａｒｌｏ方法来描述，实现了对确定性轨道模型的修正。最后，对颗粒在网格后均匀湍流中的扩散规     

稀薄气－固两相流中相间的相互作用模型

本文以稀薄气－固两相湍流流动为研究对象，推导并模化了考虑固体颗粒存在时，气相的湍流模型方程，在拉格朗日方法中实现了气－固两相间动量、湍动能的相互作用。尤其是提出当量密度及当量耗散系数两个概念后，使模型方程的型式等同于标准Ｋ－ε模型，很适合工程应用。而气相对粒子湍流扩散的影响则由类似于布朗粒子扩散的ＭｏｎｔｅＣａｒｌｏ方法来描述，实现了对确定性轨道模型的修正。最后，对颗粒在网格后均匀湍流中的扩散规律及圆管内的气－固两相湍流进行了数值模拟，表明本文提出的模型及方法很有工程应用价值。     

水平方管内固液两相流运动特性数值模拟

将周力行建立的k-ε-kp两相湍流模型引入固液两相流的研究中，对水平方管内挟沙 水流固液两相的时均特性、脉动特性以及颗粒密度分布进行了数值模拟。将计算结果与k-ε-Ap模型、动理论计算结果以及物理模型试验观测结果进行了比较，发现k-ε-k p模型数值计算和物理模型试验观测结果的一致性较好；和kεAp模型相比，由于考虑了颗粒相的湍动特性在固液两相流中的作用，k-ε-k-p两相湍流模型可以得到颗粒的脉动速度分布；和动理论相比，k-ε-kp模型无法准确地预测固相的垂向脉动速度，需要引入各向异性的两相流模型。     

水涡轮机械中的湍流固－液两相流动及磨损研究

导出了固体颗粒在任意流场中运动的Ｌａｇｒａｎｇｉａｎ方程，对此方程进行线性化，并求出了其颗粒运动方程的解析通解。使用颗粒运动方程数值求解和分析了稀疏颗粒湍流场中固体颗粒的运动。建立了湍流固－液两相流的Ｋ－ε双方程湍流模型、体积分数湍流模型、Ｅｕｎｌｅｒｉａｎ－Ｌａｇｒａｎｓｉａｎ混合湍流模型以及颗粒磨损模型，利用这些模型对一些水涡轮机械过流通道内的流动及固壁磨损进行了数值模拟，其预测结果与实验结果较为一致     

三维志k-ε-Ap模型在固液两相流时均运动特性研究中的应用

固液两相流运动特性是水动力学中的一个研究热点。本文建立的三维k-ε-Ap两相湍流模型首先研究了模型中颗粒相的两个控制参数对数值结果的影响，然后讨论了不同的颗粒平均粒径、水流流速与颗粒材料密度等三种情况下固液两相流的时均运动特性。数值计算结果和试验实测结果吻合良好。     

三维k-ε-Ap模型在固液两相流时均运动特性研究中的应用

固液两相流运动特性是水动力学中的一个研究热点。本文建立的三维k--εAp两相湍流模型首先研究了模型中颗粒相的两个控制参数对数值结果的影响,然后讨论了不同的颗粒平均粒径、水流流速与颗粒材料密度等三种情况下固液两相流的时均运动特性。数值计算结果和试验实测结果吻合良好。     

固液两相流中固体颗粒的垂直分选模型

在单个固相颗粒运动方程的基础上，进一步考虑了多颗粒条件下的颗粒之间的相互作用，并通过对液体流动特性的简化考虑，建立了固体颗粒在水流中运动的垂直分选模型。本文提出的颗粒分选模型建立在细致分析两相流运动过程中颗粒受力特点的基础上，有助于对两相流运动和沉积的各个子过程进行深入的了解，可以模拟各种颗粒在固液两相流中的运动过程和最终状态，经过统计平均得出固相颗粒的运动和分选规律。     

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.     

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.     

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。     

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.     

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.     

泥石流危害与防治

泥石流介于流水与滑坡之间的一种地质现象,其具有突然爆发、阵性、能量大的特点,来势凶猛,破坏力极强,给人民生命财产造成极大的损失和破坏。掌握其发生规律和特点,进行预报和防治是非常必要的。