无限大转动圆盘引起的气固两相流的级数解法

本文分析了一无限大转动圆盘引起的稀薄气固两相流在无穷远处的流场渐近性质,提出了相应的级数解形式,对转盘表面有强吸气和弱注射的情况得到了一系列的高精度数值解。     

滑坡动力系统的混沌效应分析

介绍了滑坡监测位移时间序列相空间重构技术,并研究了适合于计算滑坡位移时间序列Lyapunov指数的算法.通过清江库岸茅坪滑坡的实测位移数据,计算出该滑坡系统的混沌特征量Lyapunov指数λ1＞0,因此表明该滑坡动力系统具有混沌效应.     

降雨径流系列的一致性分析

降雨径流关系是否发生变化，即不同时期降雨径流关系有无显著差异是一个生产中迫切需要解决的问题。本文以山西省榆社县云簇水库降雨径流系列为例，进行了降雨径流特性的分析，内容包括降雨径流双累积曲线的特性分析、年径流系数的变化过程分析、秩和检验、回归方程的差异分析等。得出云簇水库在１９７９年以前与以后，虽年径流深、年径流系数有差异，但降雨径流关系并无明显差异的结论。     

无限大转动圆盘引起的气固两相流的积分解法

本文在作者提出的级数解基础上,把转盘的气固两相流问题转化为初值问题的积分求解,得到了一系列注射较强时的数值结果,并根据积分方法计算了级数的收敛半径。当注射足够强时,稀薄气固两相流假设在流场中某一处不再适用,本文对此分析了单个粒子的运动情况,     

三门峡站天然年径流量周期性分析

采用自相关和方差谱密度分析方法,对黄河三门峡站1470—2002年、1919～2002年和1949～2002年3个系列天然年径流量的近似周期成分进行了识别、表示和提取。研究表明：1470～2002年序列首先存在11年、其次存在3年的近似周期成分;1919-2002年和1949—2002年序列明显存在3年的近似周期成分。     

Numerical simulation of flow characteristics for a labyrinth passage in a pressure valve

A tortuous labyrinth passage consists of a series of right angle turns in a disk of high pressure control valve.In this paper,numerical simulations are made for the velocity and pressure distributions in this passage.It is shown that the "series passage" can induce a pressure dropping more effectively.The main function of the "series passage" is to induce a pressure dropping while the "parallel passage" is mainly to regulate the flow-rate.As a cross sectional area process,a series of reduction and expansion,the pressure will also see dropping and partial recovery,which is called the multistage pressure drop.By this way,the velocity can be controlled in a reasonable level anywhere in this tortuous labyrinth passage.With the fluid pressure dropping in a downwards serrated way,the pressure is higher than the local saturate vapor pressure,therefore,no cavitation is induced by the phase transition.     

The Mann-Kendall Test Modified by Effective Sample Size to Detect Trend in Serially Correlated Hydrological Series

The non-parametric Mann-Kendall (MK) statistical test has been popularly used to assess the significance of trend in hydrological time series. The test requires sample data to be serially independent. When sample data are serially correlated, the presence of serial correlation in time series will affect the ability of the test to correctly assess the significance of trend. To eliminate the effect of serial correlation on the MK test, effective sample size (ESS) has been proposed to modify the MK statistic. This study investigates the ability of ESS to eliminate the influence of serial correlation on the MK test by Monte Carlo simulation. Simulation demonstrates that when no trend exists within time series, ESS can effectively limit the effect of serial correlation on the MK test. When trend exists within time series, the existence of trend will contaminate the estimate of the magnitude of sample serial correlation, and ESS computed from the contaminated serial correlation cannot properly eliminate the effect of serial correlation on the MK test. However, if ESS is computed from the sample serial correlation that is estimated from the detrended series, ESS can still effectively reduce the influence of serial correlation on the MK test.     

减小圆盘摩擦损失新方法的实验研究

本文采秀在叶轮轮盘与泵壳体组成的间隙流场内插入一自由旋转圆盘的方法，来降低流体机械内轮盘摩擦损失。通过对插入圆盘前，后轮盘摩擦损失实验研究，结果表明：在插入圆盘前，叶轮转速，轮盘与泵壳体间轴向距离Ｓ增大会增加圆盘摩擦损失，在间隙流场内插入圆盘后，作用在叶轮轮盘的摩擦损失将减小，同时测定了圆盘转速，插入盘轴向位置地降阻影响，最后，对减阻的机理进行初步分析。     

Direct numerical simulation of Open Von Kármán Swirling Flow

Direct numerical simulations are used to investigate the Open Von Kármán Swirling Flow, a new type of unsteady three-dimensional flow that is formed between two counter-rotating coaxial disks with an axial extraction enclosed by a cylinder chamber. Solution verification shows that monotonic convergence is achieved on three systematically refined grids for average pressure at the disk periphery with a small grid uncertainty at 3.5%. Effects of the rotational speeds and flow rates on the flow field are examined. When the disks are rotating at the lowest speed, ±100 RPM, only circular vortices are formed regardless of the flow rates. When the disks are rotating at ±300 RPM and ±500 RPM, negative spiral vortex network is formed. The radial counterflow concept for such spiral vortex network is verified by examining various horizontal cuts and radial velocity component, which show radial outflows in two bands near the two disks and radial inflow in one band between them. Overall, the flow is similar to the Stewartson type flow but with significant differences for all three velocity components due to the axial suction at the upper disk center and gap between the disk periphery and chamber wall.     

一个模糊度解算的新概念

比较了现有的GPS载波相位模糊度解算方法。模糊度实数解估计可以应用包括站星几何图形的模型。也可应用不包括站星几何图形的模型，从而建立相应的模糊度搜索空间。通过数值分析发现这两个空间存在差异，但在两个空间中搜索到的模糊度整数解是一致的，从而判断两个空间有部分重叠，提出了双空间模糊度搜索概念。     

Global Assessment of Seawater Intrusion Problems (Status and Vulnerability)

In this research paper we propose a novel method to perform an integrated analysis of the status and vulnerability of coastal aquifers to seawater intrusion (SWI). The method is based on a conceptual approach of intrusion that allows to summarised results in a visual way at different spatial scales, moving from steady pictures (corresponding to instantaneous or mean values in a period) including maps and 2D conceptual cross-sections and temporal series of lumped indices. Our aim is to help in the identification of coastal groundwater bodies at risk of not achieving good chemical status according to the Water Framework Directive. The indices are obtained from available information about aquifer geometry and historical monitoring data (chloride concentration and hydraulic head data). This method may be applied even in cases where a reduced number of data are available. It does not require complex modelling and has been implemented in a GIS tool that encourages its use in other cases. Analysis of the evolution of historical time series of these indices can be used to assess resilience and trends with respect to SWI problems. This method can be also useful to compare intrusion problems in different aquifers and temporal periods.     

红层地区地下水源热泵对地下水温场的影响

地下水源热泵是地源热泵中造价最低、发展较快的一种开发利用浅层地热能资源的热泵系统。此前的研究主要是以第四系松散层内孔隙水作为热源对象,而对红层地区地下水的研究尚为空白。选取重庆红层基岩裂隙水为热源研究对象,采用对井系统带制冷(热)荷载进行试验,同时布置观测孔和温度、水位、流量等测量装置,获得试验过程中各孔内不同深度水温和水位、流量等观测数据,分析得到地下水温度场初始温度分布特点、试验过程中各孔不同深度的温度变化特点、地下水温度场在空间上随时间的变化特点等。分析结果表明:场地内地下水温场的变化主要受天然地温场及初始温度、注水井位置、注水口深度与注水温度等因素的影响。推测注水导致的温度影响范围的边界为:平面上以注水点为圆心,呈不对称近椭圆状;空间上,则以注水点为球心,呈不对称近橄榄球状。研究成果可为红层地区地下水源热泵的进一步开发利用研究提供参考。     

回流饱和挟沙力

本文针对回流的运动特点，用水槽概化模型试验，验证了回流具有平均饱和挟沙力，并对回流饱和挟沙力进行了较为细致的试验研究，通过分析其基本特性，建立了回流平均饱和挟沙力的计算公式，经验证与试验资料吻合良好。     

Effects of Zebra Mussel (Dreissena polymorpha) Colonization on Water Quality Parameters in Saginaw Bay,Lake Huron

A large-scale study of Saginaw Bay was initiated in 1990 and continued through 1993 to examine the effects of the zebra mussel colonization which began in summer/fall 1991. Saginaw Bay responded quickly to the zebra mussel colonization, as fall 1991 values of chlorophyll were similar to 1992 and 1993 values. In inner Saginaw Bay, where most zebra mussels were found, chlorophyll, kPAR, and total phosphorus values decreased, and Secchi disk depth increased during the study period, regardless of the presence or absence of zebra mussels at a specific station. At outer bay control stations no significant differences were found for chlorophyll, kPAR, and Secchi disk values. In order to examine longer-term trends, water quality data from 1979–1980 (STORET) were combined with our 1990 data (pre-zebra mussel period) and compared to values from the post zebra mussel period (fall 1991, all 1992 and 1993). At stations with high densities of zebra mussels, chlorophyll and total P decreased by 66% and 48%, respectively, and Secchi disk values increased 88%. At outer bay control stations no significant differences were found for chlorophyll or Secchi disk. When parameters were averaged throughout inner Saginaw Bay, zebra mussels caused a 59% and 43% decrease in chlorophyll and in total phosphorus and a 60% increase in Secchi disk transparency. Although zebra mussels significantly altered water quality parameters in the pelagic region of Saginaw Bay, they did not necessarily change system trophic state; rather they altered the spatial partitioning of resources.     

多目标约束下给水管网水质传感器选址优化算法的研究

利用EPANET2模拟扩展周期非稳态水力水质条件下管网节点污染物浓度变化,根据各个节点被注入污染物后,在管网模拟结束时得到的选址目标值的大小来确定节点有可能作为污染物注入的节点,目标值越大,该节点被选择的可能性越大.另外,本文提出了基本粒子群算法与遗传算法交叉、变异算子相结合的整数编码的优化算法来求解水质传感器选址问题,并编制了相应的计算程序.文中结合算例,以经过归一化后的节点平均坐标作为衡量选址结果的指标,得到了不同污染物注入开始时刻、注入持续时问和质量注入速率条件下传感器选址节点平均坐标的累计分布函数图,为传感器的选址提供参考.     

Development of a hybrid ozonation biofilm-membrane filatration process for the production of drinking water.

Drinking water sources in Norway are characterized by high concentrations of natural organic matter (NOM), low alkalinity and low turbidity. The removal of NOM is therefore a general requirement in producing potable water. Drinking water treatment plants are commonly designed with coagulation direct filtration or NF spiral wound membrane processes. This study has investigated the feasibility and potential of a hybrid process combining ozonation and biofiltration with a rotating disk membrane for treating drinking water with high NOM concentrations. Ozonation will oxidize the NOM content removing colour and form biodegradable organic compounds, which can be removed in biological filters. A constructed water was used in this study which is representative of ozonated NOM-containing water. A rotating membrane disk bioreactor downstream the ozonation process was used to carry out both the biodegradation as well as biomass separation in the same reactor. Maintenance of biodegradation of the organic matter while controlling biofouling of the membrane and acceptable water production rates was the focus in the study. Three operating modes were investigated. Removal of the biodegradable organics was consistent throughout the study indicating that sufficient biomass was maintained in the reactor for all operating conditions tested. Biofouling control was not achieved through shear-induced cleaning by periodically rotating the membrane disks at high speed. By adding a small amount of sponges in the membrane chamber the biofouling could be controlled by mechanical cleaning of the membrane surface during disk rotation. The overall results indicate that the system can favorably be used in an ozonation/biofiltration process by carrying out both biodegradation as well as biomass separation in the same reactor.     

Estimation of the water quality of the Baltic Sea and lakes in Estonia and Finland by passive optical remote sensing measurements on board vessel

In the years 1993, 1995 and 1996, passive optical remote sensing measurements taken on board ships or boats were carried out at 16 lakes in Estonia and five lakes in Finland, and also in some regions of the Baltic Sea. Simultaneously, the Secchi disk depth was measured and water samples were taken, from which chlorophyll a and suspended matter concentrations were determined in the laboratory. Using an Hitachi spectrophotometer, the attenuation coefficient spectra for filtered and unfiltered water were obtained, and the effective amount of yellow substance was estimated. The properties of the waters under consideration varied within rather wide limits, the Secchi disk depth changing from 0.4 to 8.5 m, chlorophyll concentration from 0.65 to 45 mg m^?3 and the effective amount of yellow substance from 1.8 to 32 mg L^?1. Applying the correlation method for interpretation of the optical remote sensing data, we derived algorithms for estimating the water properties in the Estonian and Finnish lakes and in the Baltic Sea. The correlation coefficients between remote sensing and other water characteristics are in the limits |r| = 0.61-0.84. This shows that despite difficulties caused by a small thickness of the‘informative’water layer and shadowing of the influence of some substance on the remote sensing spectrum by other substances in turbid, multicomponent waters, the passive optical remote sensing method is applicable for estimating the water transparency and quality in lakes and inland seas. However, the method is not suitable for (i) determining the value of a very small amount of some substance in the water if the concentrations of other optically active substances are remarkably higher or for (ii) investigating the water-bodies with a large amount of yellow substance, where extremely strong absorption of light in the water leads to an‘abnormal’shape of the remote sensing reflectance spectra. Our results confirm also that remote sensing algorithms derived for the open ocean waters are in most cases not applicable for lakes and inland seas.     

雅鲁藏布江干流年径流变化趋势及特性分析

为了分析雅鲁藏布江干流的年径流变化趋势,采用趋势分析和小波分析的方法,基于雅鲁藏布江干流羊村和奴下水文站1970~2012径流序列资料,对其干流径流的变化趋势和特性进行分析。结果表明,干流径流呈现一定的增长趋势,但趋势不显著,同时不存在显著的跳跃成分。雅鲁藏布江有较丰富的水资源可供利用,且水量来源较为稳定,受气候变化影响不显著,可为南水北调的大西线调水工程提供水源保障。     

变化水位下温度荷载对大坝工作性态的影响

现有拱坝设计规范的温度荷载假定上游库水位固定在正常蓄水位,而实际上游库水位在运行中是不断变化的。研究表明,固定水位与变化水位条件下的温度荷载存在较大的差异。以西南某拱坝为例,对同一高程处温度年变化采用傅立叶级数展开,开展变化水位下拱坝温度荷载的研究,对比分析了固定水位和变化水位下两种温度荷载及温度荷载作用下应力与变形的差异。结果表明:变化水位下温度荷载同固定水位下温度荷载的差值随深度的增加基本呈先增大后减小的趋势。在其他荷载一定时,固定水位温度荷载作用下的变形值稍大于变化水位温度荷载作用下的变形值,最大应力均要大于变化水位温度荷载作用下的最大应力。     

LS-SVM和RBF神经网络模型在降雨预测中的应用

采用相空间重构理论计算实测月降雨的延迟时间、嵌入维数、C-P饱和关联维数和Laypunov指数,证明乌尔逊河流域月降雨时间序列存在混沌现象.使用LS-SVM预测模型和RBF神经网络预测模型,两种模型对乌尔逊河流域月降雨时间序列进行对比分析.在预测精度上,LS-SVM测模型的预测精度不太理想,而RBF神经网络预测模型在降雨量很少的月份精度也很低.若想在干旱区半干旱区的降雨预测中应用,需要进一步研究.