园林池塘水缓慢流动的数值模拟研究

Fluent软件是一种流体力学中通用性较强的商业软件,应用范围十分广泛。介绍了CFD技术及Fluent软件的主要特点。以世界文化遗产——苏州拙政园为例,介绍了Fluent软件在园林不规则水面人工水力循环中的应用。计算结果为不同条件下工况条件的改变提供依据。     

计算流体力学的科学计算可视化研究进展

计算流体力学(CFD)是科学计算可视化的一个重要的研究应用领域，文章就计算流体力学的可视化技术及其研究进展进行了综述。计算流体力学的可视化内容主要有计算域的显示、计算过程及计算结果的显示与分析等。可视化技术具体可以分为对于标量场、矢量场及张量场的可视化，其中又分别包含了多种显示技术；其中，矢量场的可视化技术包括三维流场表示方法、实时动态显示以及三维交互技术仍是研究的重点，计算流动显示技术及可视化模型的软件化研究也处在迅速的发展中。     

计算流体力学数值模拟方法的探讨及应用

计算流体力学数值模拟方法可用于各种流体的绕流特性分析，在大跨桥梁、水利工程、土木工程、航空航天等领域均有着广阔的应用前景。将此方法与传统的风洞试验方法进行了对比分析，对计算流体力学数值模拟方法的特点、应用领域及基本方程等进行了阐述。通过具体算例，探讨了计算流体力学软件Fluent关键参数的设置，并将数值模拟的计算结果与风洞试验结果进行了分析比较。结果表明，Fluent计算结果与风洞试验结果在分布规律上完全一致，在建筑物表面各点的风压分布上，也吻合的较好。     

流体力学在流场计算中的作用浅析

流场计算是许多工程技术领域研究的重要方向,利用它可以设计、优化一些产品或工程,从而保证更加安全、高效的生产,以达到指导生产实践的目的.在进行流场计算的过程中,流体力学起着至关重要的作用.本文举例说明,并结合相关流体力学知识及研究现状和课题实践,浅析了流体力学在流场计算中的作用.结论表明,流场计算离不开流体力学,流体力学是流场计算的基础.     

计算流体力学在纵向式公路隧道火灾通风中的仿真

隧道一旦发生火灾，如果处理不当，将造成严重后果。为了预防和控制隧道中的火灾，必须研究烟气在隧道中的流动，进行数值仿真是一条简洁有效的途径。随着国外在计算流体力学（CFD）的兴起与发展，为这一问题的研究提供了可能。鉴于此，本研究以京珠高速公路粤境南段隧道工程为工程依托，采用计算流体力学的研究方法进行通风仿真，对研究国内公路隧道火灾通风控制具有现实意义。     

计算流体力学三维非结构网格可视化的高效算法研究

针对在流体力学数值模拟的后处理可视化发展中常见的三维非结构化网格的显示问题,提出了按节点进行循环搜索的新算法,与传统算法比较大大提高了对外边界搜索的效率,并结合自行开发的基于OpenGL的流体力学可视化软件,实现了三维计算结果的快速显示。     

串行排列的三栋建筑物间的风涡漩分布研究

本文利用计算流体力学（CFD）软件，针对串行排列的三栋建筑物的风环境，采用标准k-ε两方程湍流模型进行了数值模拟，研究分析了三种不同建筑物间的距离下的风涡漩分布特点，并定量分析了涡漩区中的风速和湍流强度，以及建筑物横截面的压力系数分布，为建筑小区的规划最优设计提供理论参考和依据。     

二平行流之间幂率流体层流剪切流动的数学模型

非牛顿流体的平行剪切流动是一种在自然界和工程实践中常见的流动。本文应用流体力学和非牛顿流体力学理论，利用Ｐｒａｎｄｔｌ边界层方程，在未作任何其它假设的情况下，得出了幂率流体平行剪切层流流动时的相似变量，给出了两充体指数ｎ相同时的常微分方程和定解条件。     

混凝土裂缝化学灌浆压力模拟与合适压力探讨

在混凝土裂缝灌浆过程中,为了解灌浆压力在裂缝中的分布情况,将混凝土裂缝化学灌浆看作一个流体力学问题来求解。根据流体力学的基本原理,采用目前国际上广泛应用的fluent软件,对灌浆过程中裂缝不同部位的压力分布状况进行了数值模拟。结果显示,在不同灌浆方式和离灌浆口不同距离的条件下,灌浆压力的沿程衰减和压力大小是不同的,据此对合适灌浆压力进行了探讨。该成果可在一定程度上用于指导灌浆施工。     

沉淀池中异重流现象的理论分析

异重流是挟沙水流的一种特殊运动形式,它的出现给净水工艺带来了极其不利的影响。对沉淀池中异重流的形成原因进行了讨论；应用流体力学的原理和方法，探讨了沉淀池中异重流的形成、运动等力学机理，建立了相应的理论分析公式，以便能减弱沉淀池中的异重流，达到提高沉淀效果的目的，更好地服务于生产实践。     

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.     

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.     

Site modelling methods for detecting hydrologic alteration of flood frequency and flood duration in the floodplain below the carlyle dam,lower Kaskaskia River,Illinois, USA

Reports concerning the influence of dams on river hydrology vary among researchers, interest groups and government agencies. These often contradicting statements may occur because changes in hydrology caused by dams are distinct for each dam and river watershed. The objective of this research was to use site specific techniques to determine if the 1967 installation of the Carlyle Dam, lower Kaskaskia River, Illinois, altered flood frequency and duration within the forested floodplain located below the dam. Results indicated a decrease in flood duration and frequency, and a decrease in annual flood frequency variation at a site 6.4 km below the dam. Pre‐dam versus post‐dam differences in flood frequency and duration at the site 32.2 km below the dam were related to climate rather than dam effects. Although dam impacts are a concern, this research shows that distance downstream from the dam and downstream tributary and watershed characteristics should be considered before assuming that the dam has changed hydrologic parameters for portions of rivers. This research also indicates that areas of the lower Kaskaskia River may still maintain hydrologic ecological integrity, and could be targeted for restoration and adaptive management purposes. Hydrologic modelling combined with river gage and on‐site well measurement techniques presented in this study could provide detailed flood frequency and duration information for land use, sociological and geomorphological questions in focus areas within river floodplains. Copyright © 2008 John Wiley & Sons, Ltd.     

浅谈优化Vray渲染在制作三维场景的应用研究

用Vray三维渲染引擎来渲染三维场景,其质量和速度是由一些影响因素和参数设置决定的,不同的参数和因素,可以得出不同的三维渲染效果.因此,分析、优化三维渲染质量和速度的影响因素,正确、合理的选择参数对提高Vray最后渲染阶段的质量和速度非常重要.     

固结、渗流和沉积控制方程研究

本文从两相流体动力学的守恒方程出发，考虑固相、液相的相对运动，推导了可以考虑场的不均匀性和流体压缩性的统一形式的控制方程，并对方程所基于的物理概念和相互联系进行了必要的分析。通过对方程适当形式的表达，可导出用于大、小变形固结、渗流和沉积的简化方程，显示了在不同领域的三个理论存在一定的统一性。方程推导过程并未对本构关系加以限制，适用范围较广。依据实际问题的要求，作了不同形式的简化。     

四川省及重庆市中型水电站效益分析

该文分析了四川省及重庆市几座中型水电站的调查材料表明：四川省及重庆市中型水电站不仅在川渝主网和地方电网中起着很大的作用，并具有巨大的社会效益，同时还有综合利用效益，说明修建中型水电站的优越性．     

掺MgO混凝土的宏细观试验研究

利用MgO膨胀剂的延迟微膨胀效应能显著提高大体积混凝土的力学性能,产生的预压应力还能有效提高大体积混凝土抵抗温度开裂的能力,但目前对其微观机理研究不多。采用宏观与微观相结合的方式,研究了不同活性指数、不同掺量的MgO混凝土的力学性能,利用SEM/EDS微观分析手段揭示了MgO对混凝土性能影响的作用机理。试验结果表明:MgO取代部分水泥掺入混凝土中,混凝土的力学性能降低;掺量为4%～5%时,活性指数为100s的MgO混凝土的膨胀率大于活性指数为50 s的MgO混凝土;MgO混凝土的膨胀特性与Ca,Si,Mg,Al等元素的分布情况有关,掺入的MgO将改变界面区Ca,Si,Mg元素的富集特性,Ca元素和Mg元素更易于在界面区富集,导致混凝土宏观力学性能的降低。     

Statistical tools for thermal regime characterization at segment river scale: Case study of the Ste‐Marguerite River

Suitable thermal fish habitats are constrained by both maximum and minimum temperature tolerances. A multivariate and geostatistical approach was developed to estimate stream thermal characteristics at the river segment scale. Data from 22 temperature‐monitoring stations during summer 2007 were used to estimate monthly maximum temperature as well as thermal characteristics such as the number of events, the cumulative degree–days and the associated duration over specific temperature thresholds of 19 and 21°C. The probability of exceeding these temperature thresholds has also been interpolated. The methodology relies on the construction of a multivariate space using physiographic and hydrological characteristics of gauging stations as inputs in a canonical correlation analysis (CCA). A geostatistical interpolation technique, ordinary kriging, was subsequently used to perform interpolation in the physiographical space constructed using CCA. Results from this study were obtained for thermal characteristics estimated into two different interpolation spaces: (1) a 7 metrics space, and (2) an 8 metrics space. Cross‐validation technique has been performed and satisfactory results were obtained. Kriging thermal characteristics (magnitude and duration) into the 7 metric space for a 19°C threshold exceedance leads to best results with Relative Root Mean Square Error (RRMSE) ranging between 9.66 and 15.08%. The study shows that kriging in a multivariate space is a promising tool for water resources managers, especially in cases where risk mapping for lethal or sub‐lethal temperature thresholds may be required for a specific fish species. Copyright © 2010 John Wiley & Sons, Ltd.     

基于MIDAS软件探讨施工工序对深基坑稳定性的影响

基于武汉地铁名都站深基坑工程与水文地质勘察资料,建立了三维工程地质仿真计算模型。依据名都站深基坑开挖支护方案,利用有限元软件MIDAS的摩尔-库仑本构模型,对武汉地铁名都站深基坑施工过程中,不同施工工序下每步开挖之后,基坑的变形情况做仿真模拟计算,并对比分析其对基坑稳定性的影响。结果表明:基坑围护结构的变形情况与施工工序有很大的关系,施工工序越合理,上部土体变形越小,反之越大。因此,在基坑工程的施工过程中,要注重施工步骤的划分与合理安排,从而保证基坑工程的安全。研究成果为以后武汉地区基坑工程的施工设计提供了值得借鉴的经验。