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Analytical Models for Velocity Distributions in Compound Channels with Emerged and Submerged Vegetated Floodplains

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Chinese Geographical Science 2017年第4期27卷 577-588页

作者： ZHANG Mingwu JIANG Chunbo HUANG Heqing Gerald Charles NANSON CHEN Zhengbing YAO Wenyi Yellow River Institute of Hydraulic Research Yellow River Conservancy Commission State Key Laboratory of hydroscience and engineering Department of HydraulicsTsinghua University Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences School of Earth and Environmental Sciences University of Wollongong

The lateral distributions of depth-averaged velocity in open compound channels with emerged and submerged vegetated floodplains were analyzed based on the analytical solution of the depth-integrated Reynolds-Averaged Navier-Stokes equation with a term to account for the effects of *** three cases considered for open channels were two-stage rectangular channel with emerged vegetated floodplain,rectangular channel with submerged vegetated corner,and two-stage rectangular channel with submerged vegetated floodplain,*** predict the depth-averaged velocity with submerged vegetated floodplains,we proposed a new method based on a two-layer approach where flow above and through the vegetation layer was described ***,further experiments in the two-stage rectangular channel with submerged vegetated floodplain were carried out to verify the *** analytical solutions of the cases indicated that the corresponding analytical depth-averaged velocity distributions agree well with the simulated and experimental *** analytical solutions of the cases with theoretical foundation and without programming calculation were reasonable and applicable,which were more convenient than numerical *** analytical solutions provided a way for future researches to solve the problems of submerged vegetation and discontinuous phenomenon of depth-averaged velocity at the stage point for compound *** the hydraulics of flow in compound channels with vegetated floodplains is very important for supporting the management of fluvial processes.

关键词：沉水植被冲积平原速度分布渠道复合解析模型矩形通道平均速度

中国GNSS-R航空飞行试验初步结果之一:土壤湿度测量(英文)

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Science Bulletin 2015年第10期60卷 964-971,I0008页

作者：万玮白伟华赵利民龙笛孙越强孟祥广谌华崔喜爱洪阳 State Key Laboratory of hydroscience and engineering Tsinghua University Department of Hydraulic engineering Tsinghua University Institute of Remote Sensing and Digital Earth Chinese Academy of Sciences Meteorological Observation Center China Meteorological Administration

全球导航卫星反射信号遥感(Global Navigation Satellite System Reflectometry,GNSS-R)是近年来新兴的学科交叉研究领域,其通过接收导航卫星(如GPS、北斗)的海面/陆面反射信号来获取参数信息(如海面高度、土壤湿度等).GNSS-R的最终目... 详细信息

全球导航卫星反射信号遥感(Global Navigation Satellite System Reflectometry,GNSS-R)是近年来新兴的学科交叉研究领域,其通过接收导航卫星(如GPS、北斗)的海面/陆面反射信号来获取参数信息(如海面高度、土壤湿度等).GNSS-R的最终目标是实现大范围、全天时、高时间分辨率的星载观测,航空飞行试验是实现星载可行性论证的必要条件.本文报道中国2014年5月于河南郑州开展的GNSS-R航空飞行试验概况,并给出陆表参数——土壤湿度的估算方法和结果分析,为中国GNSS-R观测试验开展、自主载荷研制、陆面观测数据处理等提供参考.

关键词：检索模型土壤水分中国运动全球导航卫星系统空气地球物理参数观察能力

Analytical solution to one-dimensional mathematical model of flow and morphological evolution in open channels

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Science China(Technological Sciences) 2020年第12期63卷 2606-2616页

作者： DING Yun LI ZuiSen SHI YongZhong ZHONG DeYu State Key Laboratory of Hydrology-Water Resources and Hydraulic engineering Hohai UniversityNanjing 210098China College of Water Conservancy and Hydropower engineering Hohai UniversityNanjing 210098China Zhejiang Institute of Hydraulics and Estuary Hangzhou 310008China Zhejiang Provincial Key Laboratory of Hydraulic Disaster Prevention and Mitigation Hangzhou 310008China Joint-Sponsored State Key Laboratory of Plateau Ecology and Agriculture Qinghai UniversityXining 810016China State Key Laboratory of hydroscience and engineering Tsinghua UniversityBeijing 100084China

The evolution of open-channel flow and morphology can be simulated by one-dimensional(1D) mathematical models. These models are typically solved by numerical or analytical methods. Because the behavior of variables can be explained by explicit mathematical determinations,compared to numerical solutions,analytical solutions provide fundamental and physical insights into flow and sediment transport mechanisms. The singular perturbation technique derives a hierarchical equation of waves and describes the evolutionary nature of disturbances in hyperbolic systems. The wave hierarchy consists of dynamic,diffusion,and kinetic waves. These three types of waves interact with each other in the process of propagation. Moreover,the Laplace transform is implemented to transform partial differential equations into ordinary differential equations. Analytical expressions in the wave front are subtracted by the approximation of kinetic and diffusion models. Moreover,an analytical solution consists of a linear combination of the kinetic wave front and the diffusion wave front expressions,pursuing to describe the physical mechanism of motion in open channels as completely as possible. Analytical solutions are presented as a combination of exponential functions,hyperbolic functions,and infinite series. The obtained analytical solution was further applied to the simulation of flood path and morphological evolution in the Lower Yellow River. The phenomenon of increased peak discharge in the downstream reach was successfully simulated. It was encouraging that the results were in good agreement with the observed data.

关键词： open channel mathematical model analytical solution Laplace transform morphological evolution

3D mode discrete element method with the elastoplastic model

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Frontiers of Structural and Civil engineering 2012年第1期6卷 57-68页

作者： Wei HU Feng JIN Chong ZHANG Jinting WANG State Key Laboratory of hydroscience and engineering Tsinghua UniversityBeijing 100084China China State Construction Property Corp.Ltd. Beijing 100037China Chengdu Hydroelectric Investigation&Design Institute of SPC Chengdu 610072China

The three-dimensional mode-deformable discrete element method(3MDEM)is an extended distinct element approach under the assumptions of small strain,finite displacement,and finite rotation of *** deformation of blocks is expressed by the combination of the deformation modes in *** this paper,the elastoplastic constitutive relationship of blocks is implemented on the 3MDEM platform to simulate the integrated process from elasticity to plasticity and finally to *** overcome the shortcomings of the conventional criterion for contact fracturing,a new criterion based on plastic strain is *** approach is verified by two numerical ***,a cantilever beam is simulated as a comprehensive case study,which went through elastic,elastoplastic,and discontinuous fracture stages.

关键词： mode discrete element method elastoplastic numerical method discontinuum contact

Effects of liquid compressibility on bubble-bubble interactions between oscillating bubbles

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Journal of Hydrodynamics 2016年第5期28卷 832-839页

作者：张宇宁闵琪张宇宁杜小泽 State Key Laboratory of hydroscience and engineering Tsinghua University Beijing 100084 China Beijing Key Laboratory of Emission Surveillance and Control for Thermal Power Generation School ofEnergy Power and Mechanical Engineering North China Electric Power University Beijing 102206 China Key Laboratory of Condition Monitoring and Control for Power Plant Equipment (Ministry of Education) North China Electric Power University Beijing 102206 China Institute of Nuclear and New Energy Technology Tsinghua University Beijing 100084 China College of Mechanical and Transportation engineering China University of Petroleum Beijing 102249 China

The mutual interaction between cavitation bubbles plays an important role in the physical processes of cavitation. In this paper, a complete model is developed for modelling the mutual interaction between cavitation bubbles with the effects of liquid compressibility fully included. It is found that the liquid compressibility is an important parameter in the determination of the direction of the force （the attraction or repulsion force）, as well as the magnitude of the force. The influences of the liquid compre- ssibility on the mutual interaction force can be categorized into three terms： the first is a new term added on the mutual interaction force in incompressible liquids and this term will vanish if the sizes of two bubbles are equal, the second is the radiation damping term, the third one can be considered as a correction of the mutual interaction force in incompressible liquids with a coefficient and this correction will be prominent for small bubbles and a high ambient pressure.

关键词： cavitation Bjerknes force liquid compressibility interacting bubbles bubble cloud

GSTARS computer models and their applications, Part Ⅱ: Applications

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International Journal of Sediment Research 2008年第4期23卷 299-315页

作者： Francisco J.M.SIM■ES Chih Ted YANG Research Hydrologist US Geological Survey Geomorphology and Sediment Transport Laboratory4620 Technology Drive Suite 400 Golden CO 80403 USA Borland Prof. of Water Resources and Director of hydroscience and Training Center Department of Civil and Environmental Engineering Colorado State UniversityFort Collins CO 80523-1372 USA

In part 1 of this two-paper series, a brief summary of the basic concepts and theories used in developing the Generalized Stream Tube model for Alluvial River Simulation (GSTARS) computer models was presented. Part 2 provides examples that illustrate some of the capabilities of the GSTARS models and how they can be applied to solve a wide range of river and reservoir sedimentation problems. Laboratory and field case studies are used and the examples show representative applications of the earlier and of the more recent versions of GSTARS. Some of the more recent capabilities implemented in GSTARS3, one of the latest versions of the series, are also discussed here with more detail.

关键词： Computer model Reservoir River Sediment transport Unit stream power

Strategies for managing reservoir sedimentation

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International Journal of Sediment Research 2009年第4期24卷 369-384页

作者： Zhao-yin WANG 1 and Chunhong HU 21 Prof., State Key Lab of hydroscience and engineering, Tsinghua University, Beijing 100084, China. 2 Prof., Secretary General of International Research and Training Center on Erosion and Sedimentation, Beijing 100048, China and Vice President of China Institute of Water Resources and Hydropower Research, No. A-1, Fuxing Rd, Beijing 100038, China. Prof. State Key Lab of Hydroscience and Engineering Tsinghua University Beijing 100084 China Prof. Secretary General of International Research and Training Center on Erosion and Sedimentation Beijing 100048 China and Vice President of China Institute of Water Resources and Hydropower Research No. A-1 Fuxing Rd Beijing 100038 China

Sediment deposition in reservoirs has caused the loss of 66% of the reservoir capacity in China. The main sedimentation control strategies are: 1) storing the clear water and releasing the turbid water; 2) releasing turbidity currents; 3) Draw-down flushing and empty flushing; and 4) dredging. The paper summarizes these strategies with examples. Sediment transport in many Chinese rivers occurs mostly during the 2-4 month flood season, that is, 80-90% of the annual sediment load is transported with 50-60% of the annual runoff. By storing the clear water after the flood season and releasing the turbid water during the flood season, less sediment deposits in the reservoir while the reservoir is still able to store enough water for power generation in the low flow season. The Three Gorges and Sanmenxia reservoirs apply this strategy and control sedimentation effectively. Turbidity currents have become the main sedimentation control strategy for the Xiaolangdi Reservoir. Empty flushing involves reservoir draw-down to temporarily establish riverine flow along the impound reach, flushing the eroded sediment through the outlets. Case studies with the Hengshan Reservoir and Zhuwo Reservoir are presented. Jet dredgers have been used to agitate the reservoir deposit so that the deposit is released from the reservoir with currents. The sediment releasing efficiency is 30-100% for storing the clear and releasing the turbid; 6-40 % for turbidity current; and 2,400-5,500% for empty flushing. Empty flushing causes high ecological stress on the ecosystem to the downstream reaches. Storing the clear and releasing the turbid is the best strategy to control reservoir sedimentation while achieving hydro-power benefit and maintain ecological stability.

关键词： Reservoir sedimentation Storing clear and releasing turbid Flushing Turbidity current Three Gorges Reservoir

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河岸带潜流层动态过程与生态修复

水科学进展 2013年第4期24卷 589-597页

作者：夏继红陈永明王为木韩玉玲刘海洋胡玲河海大学水利水电学院 National Center for Computational hydroscience and engineering the University of MississippiMS Oxford 38655 USA 浙江省河道管理总站

河岸带潜流层是河岸带内地表水与地下水相互作用的生态交错带,在水文地理学、生态学、环境学上含义不尽相同。河岸带潜流层具有复杂的垂向、横向、纵向结构特征,其边缘效应显著,表现为泥沙、水流、生物、环境化学因子之间的复杂动态过程... 详细信息

河岸带潜流层是河岸带内地表水与地下水相互作用的生态交错带,在水文地理学、生态学、环境学上含义不尽相同。河岸带潜流层具有复杂的垂向、横向、纵向结构特征,其边缘效应显著,表现为泥沙、水流、生物、环境化学因子之间的复杂动态过程,主要包括水动力动态过程、生态学过程、溶质循环与化学过程等。水动力动态过程是驱动条件,氧气浓度是生态过程、溶质循环和化学过程的决定性因素。在各动态过程的驱动下,河岸带潜流层具有调蓄洪水、削减污染、净化缓冲环境和提供适宜栖息地等功能。针对河岸带潜流层功能退化的问题,需开展健康诊断,明确致病机理,实施适宜的生态修复。未来中国在开展河岸带潜流层研究时,应根据中国河岸带特点,采用示踪试验、数值模拟等方法,集成GIS等现代技术手段,研究多尺度下,水文条件、地形变化、土壤渗透系数、河岸带建设方式、植被分布等对河岸带潜流层水文、热传导、生化、生态等的影响机制,准确界定河岸带潜流层区域范围,制定适宜的生态修复策略。

关键词：河岸带潜流潜流生物边缘效应生态修复

Experimental study of water curtain performance for gas storage in an underground cavern

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Journal of Rock Mechanics and Geotechnical engineering 2009年第1期1卷 89-96页

作者： Zhongkui Li Kezhong Wang Anmin Wang Hui Liu State Key Laboratory of hydroscience and engineering Tsinghua University Beij＇ing 100084 China School of Civil engineering andArchitecture Zhejiang University of Technology Hangzhou 310014 China

An artificial water curtain system is composed of a network of underground galleries and horizontal boreholes drilled from these ***-grouting measures are introduced to keep the bedrock saturated all the *** system is deployed over an artificial or natural underground cavern used for the storage of gas（or some other fluids） to prevent the gas from escaping through leakage paths in the rock *** experimental physical modeling system has been constructed to evaluate the performance of artificial water curtain systems under various *** conditions include different spacings of caverns and cavern radii located below the natural groundwater *** principles of the experiment,devices,design of the physical model,calculation of gas leakage,and evaluation of the critical gas pressure are presented in this *** result shows that gas leakage is strongly affected by the spacing of water curtain boreholes,the critical gas pressure,and the number and proximity of storage *** hydraulic connection between boreholes is observed to vary with depth or location,which suggests that the distribution of water-conducting joint sets along the boreholes is also *** designing the drainage system for a cavern,drainage holes should be orientated to maximize the frequency at which they encounter major joint sets and permeable intervals studying in order to maintain the seal on the cavern through water *** experimental results provide a significant contribution to the theoretical controls on water curtains,and they can be used to guide the design and construction of practical storage caverns.

关键词： artificial water curtain model test storage cavern gas pressure