Using an eddy‐resolving technique to assess the effects of reservoir operation on the bend flow in Yangtze River,China

With increasing computing power over the last decade, eddy‐resolving methods in hydraulics engineering have been widely used to investigate the turbulence structure in natural rivers, where accurate field measurements were difficult to conduct and investigate. A detached eddy simulation (DES) model was developed on the basis of the k‐ω‐SST (shear stress transport) eddy‐viscosity model within the framework of an unstructured‐mesh Semi‐implicit Eulerian–Lagrangian Finite Element (SELFE) hydrodynamic model. The DES model was then applied to simulate the bend flow in the upper Yangtze River, and the calculation efficiency was enhanced through parallelized computation to mitigate the high computation costs involved in the DES modelling. The time‐averaged velocity, turbulent intensity and Reynolds stress were compared, using DES modelling and acoustic Doppler current profiler (ADCP) measuring results, indicating good agreement, especially in the near‐bed region. The coupled relationship between the turbulent flow and riverbed terrain was also investigated through extracting and analysing the high‐order statistical variables reflecting the turbulence structure, including non‐hydrostatic pressure, vorticity and helicity, indicating the fluctuated amplitude of non‐hydrostatic pressure can reach to 100 Pa, and the stripe distribution of non‐hydrostatic pressure and vorticity had an orthogonality relation. At the same time, the streamwise velocity at the middle of the HLM bend was found to be decreased at least 0.7 m/s because of unsteady process smoothing and backwater effects attributable to water releases and storage of the reservoirs located upstream and downstream of the HLM bend. The developed unstructured‐mesh DES model will provide a new tool to study turbulent flows in a natural river and assess the effect of reservoir operations on river flows.     

基于有限体积法的河网水动力并行计算模型

针对具有干河床、急缓流态交替的河网水动力模拟,采用MUSCL-Hancock有限体积格式离散Saint-Venant方程组,运用汊点水位预测-校正法处理河网汊点连接条件,建立了断面与河道完全数值解耦的复杂河网水动力模型。运用OpenMP和OpenACC编程模式分别实现了CPU,GPU并行计算。采用经典算例对模型计算精度进行了验证,采用珠三角河网实际算例对不同并行计算方式的加速效果进行了分析。算例研究表明,该模型具有良好的稳定性和计算效率,可适用于陡坡河道水动力模拟,具有较好的推广应用价值。     

A 2-D HYDRODYNAMIC MODEL FOR THE RIVER, LAKE AND NETWORK SYSTEM IN THE JINGJIANG REACH ON THE UNSTRUCTURED QUADRANGLES

The main river,the Dongting Lake and river networks in the Jingjiang reach of the Yangtze River constitute a complex water system,for which a full 2-D hydrodynamic model is established instead of the traditional 1-D or compound models for simulation of such complex systems,based on the latest developments of computer technologies and numerical methods.To better handle irregular boundaries and keep the computation cost well in a reasonable limit,unstructured grids of moderate scale are used. In addition,a dynamic boundary tracking method is proposed to simulate variable flow domains at different floods,especially,when the moderate scale gird can not describe flows in narrow river-network channels at low water levels.Theθsemi-implicit method and the Eulerian-Lagrangian Method(ELM)are adopted,which make the model unconditionally stable with respect to the gravity wave speed and Courant number restrictions.Properties and efficiency of the model are discussed,and it is concluded that the new model is robust and efficient enough for the simulation of a big,complex water system.Validation tests show that the simulation results agree well with field data.It takes about 0.96 h to complete the computation of a 76 d flood,which indicates that the model is efficient enough for engineering applications.     

长江科学院河流水沙数学模型研究进展与展望

自20世纪50年代末,长江科学院开始研发河流水沙数学模型,至今已有60多年不间断研发与应用历史,形成了“河流（HELIU）”系列软件。综述了长江科学院水库泥沙、河流一维、二维、（准）三维等水沙模型及其它水沙数学模型实例（包括河流水沙估算模型、河流水沙专题数模研究、引进吸收的河流水沙数学模型）,以及水沙数值模拟关键技术的研究进展。分析展望了河流水沙数学模型今后研发工作的 4 方面任务：构建模型体系、完善现有模型、拓展模型领域和研究关键技术。     

闸坝调控下重污染河流污染物迁移规律研究

以沙颍河槐店闸为研究对象,构建了闸坝调控作用下二维水动力-污染物迁移模型,根据试验获取的数据对模型进行率定和检验。结果表明:闸坝的存在对河流水环境系统具有一定负面影响,但是合理的闸坝调控能够改善河流水质,减小突发性水污染事故发生的概率;该模型可以有效地模拟计算闸坝调控作用下污染物的迁移过程。     

长江南通段大型排污口退水影响预测

根据长江南通段的水动力、污染物输移特征,建立了平面二维非稳态水流水质模型,并利用实测的水文资料进行模型验证。结果表明,无论是流场的整体形态还是验证点的水位、流速都与实际情况符合较好。以南通市观音山污水处理厂、开发区第一污水处理厂入江整合排污口为研究实例,预测了该排污口在90%保证率下尾水对纳污江段的水环境影响,旨在为该类型河段的排污口退水影响预测提供技术依据。     

基于Delft3D-flow模型的长江口盐度扩散规律模拟

为了研究长江口环流动力过程下的河口盐度扩散和分层混合机制,采用河口三维模型(Delft3D-flow)模拟了长江口盐度分层扩散规律和扩散系数变化对河口分层的影响。通过模拟实际水文情况下的长江口水动力过程,反映了该区域受到较强的径潮流动力作用后,对盐度在涨落潮周期内的垂向混合分层产生了重要影响,进一步验证了分层河口紊动扩散系数对盐度的水平扩散输移、垂向非稳定层化和混合的影响均较大。模拟结果较好地反映了河口在复杂水动力过程下盐度扩散和分层规律。     

DWSM动态并行计算技术

针对DWSM计算模式鲁棒性低、计算时间长、无法实现多核计算等局限性,对模型的算法和存储规则进行相应改进。在遵从DWSM计算逻辑顺序的基础上,抛弃原计算单元顺序表模式关于虚拟河道的假设,采用流域分区概念进行河网树结构的模式设计,在基于叶节点并行计算的基础上研究动态分级并行计算技术,以进一步完善计算模式。以黄河宁蒙段流域为实例,计算结果表明,算法的优化极大地提高了DWSM的计算效率,增强了其对大范围、具有复杂河网结构流域水沙规律研究的适用性。     

Hybrid Adaptive Neuro-Fuzzy Models for Water Quality Index Estimation

Soft computing models are known as an efficient tool for modelling temporal and spatial variation of surface water quality variables and particularly in rivers. These model’s performance relies on how effective their simulation processes are accomplished. Fuzzy logic approach is one of the authoritative intelligent model in solving complex problems that deal with uncertainty and vagueness data. River water quality nature is involved with high stochasticity and redundancy due to the its correlation with several hydrological and environmental aspects. Yet, the fuzzy logic theory can give robust solution for modelling river water quality problem. In addition, this approach likewise can be coordinated with an expert system framework for giving reliable and trustful information for decision makers in enhancing river system sustainability and factual strategies. In this research, different hybrid intelligence models based on adaptive neuro-fuzzy inference system (ANFIS) integrated with fuzzy c-means data clustering (FCM), grid partition (GP) and subtractive clustering (SC) models are used in modelling river water quality index (WQI). Monthly measurement records belong to Selangor River located in Malaysia were selected to build the predictive models. The modelling process was included several water quality terms counting physical, chemical and biological variables whereas WQI was the target variable. At the first stage of the research, statistical analysis for each water quality parameter was analyzed toward the WQI. Whereas in the second stage, the predictive models were established. The finding of the current research provides an authorized soft computing model to determine WQI that can be used instead of the conventional procedure that consumes time, cost, efforts and sometimes computation errors.     

长江模拟器的理论方法与实践探索

长江大保护是新时期国家重大战略之一。以水为纽带的长江经济带绿色发展面临诸多难题，如流域上、中、下游、左岸和右岸以及陆海统筹的系统治理，长江保护法实施的监管，变化环境下流域综合规划管理等。2019年提出了“长江模拟器”的构想，本文在此基础上系统总结了其概念和内涵，构建了长江模拟器的系统框架，即本质是以长江流域为对象，以流域水循环为纽带，将自然过程与人文过程相耦合而研发的流域模拟系统及科学装置。在明晰长江模拟器功能和应用、关键科学问题及学科需求等基础上，阐述了长江模拟器的理论体系，包括地球系统科学理论、经济社会科学理论、信息科学理论3大类；构架了长江模拟器的方法体系，包括5大类关键技术(智能感知技术、数据融合技术、计算支撑技术、应急处理技术和服务构建技术)、4大类主要方法(计算资源调配方法、数值模拟计算方法、人工智能模拟方法和优化决策调控方法);总结了长江模拟器面向6大方面的服务体系，即科技创新服务、综合治理服务、政府决策服务、应急管理服务、公众文化服务和数据应用服务。最后介绍了目前已开发的“长江模拟器1.0”应用实例。通过长江模拟器的建设，可为大江大河流域综合协调管理，也可为水利、环境保...     

Mathematical model for flood routing in Jingjiang River and Dongting Lake network

The main stream of the Yangtze River, Dongting Lake, and the river network in the Jingjiang reach of the Yangtze River constitute a complex water system. This paper develops a one-dimensional (1-D) mathematical model for flood routing in the river network of the Jingjiang River and Dongting Lake using the explicit finite volume method. Based on observed data during the flood periods in 1996 and 1998, the model was calibrated and validated, and the results show that the model is effective and has high accuracy. In addition, the one-dimensional mathematical model for the river network and the horizontal two-dimensional (2-D) mathematical model for the Jingjiang flood diversion area were coupled to simulate the flood process in the Jingjiang River, Dongting Lake, and the Jingjiang flood diversion area. The calculated results of the coupled model are consistent with the practical processes. Meanwhile, the results show that the flood diversion has significant effects on the decrease of the peak water level at the Shashi and Chenjiawan hydrological stations near the flood diversion gates, and the effect is more obvious in the downstream than in the upstream.     

水动力模型在平原感潮河网地区的研究与应用

根据平原感潮河网的水力特性，研究复杂河网非恒定流计算问题，利用圣维南方程组、节点连续方程及边界条件建立了水动力数学混合模型。将模型应用于宁波市鄞东南水系的河网计算，并利用2005年“麦莎”台风实测水文资料对模型做了检验。验证结果表明，建立的水动力数学模型是可行的，可以用于平原感潮河网地区的水力计算。     

Identification of River Sections for Domestic Water Supply along the Yangtze River in Jiangsu Province, China

This paper presents major findings from a recent study aiming to systematically determine suitable river sections for local domestic water supply along the Yangtze River in Jiangsu Province, China. On the basis of analysis on the current riverbank utilization and bank stability, accessible and stable river sections in the region were selected. The water quality in these river sections was then studied using a two-dimensional unsteady flow and pollutant transport/transformation model, RBFVM-2D. The model was calibrated and verified against the hydrodynamic data, water quality data and remote sensing data collected from the river. The investigation on the pollution sources along the river identified 56 main pollution point sources. The pollution zones downstream of these point sources are the main threat for the water quality in the river. The model was used to compute the pollution zones. In particular, simulations were conducted to establish the relationship between the extent of the pollution zone and the wastewater discharge rate of the associated point source. These water quality simulation results were combined with the riverbank stability analysis to determine suitable river sections for local domestic water supply.     

Sediment transport following water transfer from Yangtze River to Taihu Basin

To meet the increasing need of fresh water and to improve the water quality of Taihu Lake, water transfer from the Yangtze River was initiated in 2002. This study was performed to investigate the sediment distribution along the river course following water transfer. A rainfall-runoff model was first built to calculate the runoff of the Taihu Basin in 2003. Then, the flow patterns of river networks were simulated using a one-dimensional river network hydrodynamic model. Based on the boundary conditions of th...     

长江科学院河流专业研究进展综述——以《长江科学院院报》30年来发表的论文为例

以长江科学院河流研究所20世纪80年代以来发表在《长江科学院院报》上的论文为基础,概述了近30 a来紧密结合长江流域综合规划、重大水利工程建设、长江河道治理方略等方面开展的有关长江河流泥沙、河道治理及河流模拟研究的主要工作成果。可见,30 a来长江科学院河流研究所在长江泥沙运动基本规律、河流动力学的学科交叉发展、河流物理模型基础理论、河流数学模型基本方法以及典型河段治理工程经验等方面的研究取得了长足进展,为长江河道治理、重大水利工程建设提供了大量的科学依据。并认为在未来一段时间,还需更进一步探索长江流域宏观泥沙问题、深入研究长江流域细观泥沙问题、突出长江河道与湖泊的综合治理等,才能更好地服务于更大范围和更高目标的治江事业。     

NUMERICAL SIMULATION OF BED TOPOGRAPHY CHANGES INDUCED BY DEEP WATER NAVIGATION CHANNEL PROJECT IN THE YANGTZE ESTUARY

1 .　INTRODUCTIONWiththedevelopmentofindustriesintheYangtzeestuary ,moreandmoreprojects ,suchasportdevelopments ,waterwayconstruction ,landreclamationaswellascoastalprotectionworks,havebeenconductingintheestuary .Moredetailedknowledgeofthetidehydrodynamicsandsedimenttransportmechanisminthewaterisneededforconstructionandmanagementofthe projectsbe causeofthedifficultiesinmodelingthecharacter isticsoffinecohesivesedimentmovementandthecomplicatedflowsdrivenbyriverdischarge ,tide ,stormsurgeand…     

引江济太工程水源地河床稳定性分析

引江济太工程水源地位于长江澄通段的福山倒套内,其河床稳定性是影响引江济太工程成败的关键。因此,根据大量实测水下地形资料,对福山倒套的河势演变进行分析,研究倒套河床形态特征对自身水动力结构的影响。同时,结合二维水量模型对福山倒套淤积的形势进行数值模拟和预测。结果表明:①倒套内部水位降低,但变化不明显;②倒套内部流场流速整体下降,尤其是倒套口门处流速值减小较大;③倒套虽然处于淤积阶段,但倒套口门段较为稳定。因此,适时疏浚上部串沟是维持倒套稳定之关键。     

闸控感潮河段重金属迁移转化规律研究

以长江感潮江段的某入江河道为典型案例,根据闸控条件下的水文特征、污染物迁移转化特性分别建立了由入江河道及长江相关河段构成的动态二维水动力及重金属数学模型,模拟分析了闸门控制下入江河道的水流运动规律、点源连续排放的重金属浓度随时间变化及二维平面分布特征。模拟结果表明:在长江潮汐、水闸控制影响下,入江河道内重金属浓度在一定范围内呈现周期性波动的现象,重金属浓度整体呈增大趋势,随着污水排放时间的推移,河道内各断面处重金属浓度最大值和波动区间均趋于稳定;典型超周期内,河道内落潮流污染带长度大于涨潮流。重金属在潮汐河道内的变化是一个非常复杂的过程,对这一过程的模拟,可以为河道水质治理和污染防治提供技术依据。     

基于LINUX和MPICH2 的高性能科学计算集群搭建及其性能评测

在水利工程计算中,单机计算已经不能满足实际科研和生产的需要,大型工程的设计、施工、管理和科学研究都越来越依赖于高性能科学计算。采用并行计算和计算机网络技术构建高性能科学计算集群,能够有效提高计算速度并降低运算成本。本文探讨了基于Beowulf集群模型,利用普通PC机和以太网,通过在LINUX操作系统下搭建基于MPICH2的并行计算集群,实现低成本并行计算平台的技术,并介绍了利用Linpack测试对并行计算集群进行性能评测的具体方法。这一技术对于解决较大规模科学和工程计算问题具有重要的实用价值和经济意义。     

长江口盐水入侵数值模型研究

本文利用ECOM模式建立了一个长江口水动力盐度三维数值模型。当水底地形变化比较剧烈时，原ECOM模式中水平扩散项的计算就可能产生虚假的流场和物质输运，所以文中首先对ECOM模式物质输运方程的水平扩散项计算方法进行改进，采用返回z坐标系计算，离散变量利用σ层二次Lagrange插值得到。对于改进方法，文中采用Huang＆spaulding提出的数值试验进行验证，证明此方法大大地提高了水平扩散项的计算精度。改进模型采用长江口实测水文资料进行率定验证，计算和分析了南北槽垂向盐度分布和盐水通量过程，结果表明，模型能较好反映测点盐度变化过程，也能较好地模拟出垂向表底层的盐度差异。