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

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water Science and Engineering 2012年第3期5卷 259-268页

作者： Zuo-tao XIE Fang-li YANG Xiao-li FU Changjiang institute of Survey Planning Design and Research Wuhan 430010 P. R. China Changjiang waterway {1. Design and Research Institute Wuhan 430010 P R. China State Key Laboratory of water {1. and hydropower Engineering Science Wuhan University Wuhan 430072 P. R. China

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 （l-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 1.96 and 1.98, 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.

关键词： Jingjiang River," Dongting Lake," Jing/iang flood diversion area," flood routing," rivernetworks 1.D and 2-D coupled model

Comparison of dominant frequency attenuation of blasting vibration for different charge structures

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第2期14卷 448-459页

作者： Pengchang Sun Wenbo Lu Junru Zhou Xincheng Huang Ming Chen Qi Li State Key Laboratory of water {1. and hydropower Engineering Science Wuhan UniversityWuhan430072China School of Resource and Environmental Engineering Wuhan University of Science and TechnologyWuhan430081China Changjiang institute of Survey PlanningDesign and ResearchWuhan430010China

Dominant frequency attenuation is a significant concern for frequency-based criteria of blasting vibration *** is necessary to develop a concise and practical prediction equation describing dominant frequency *** this paper,a prediction equation of dominant frequency that accounts for primary parameters influencing the dominant frequency was proposed based on theoretical and dimensional *** blasting experiments were carried out in the Chiwan parking lot for collecting blasting vibration data used to conduct regression analysis of the proposed prediction *** fitting equations were further adopted to compare the reliability of three different types of dominant frequencies in the proposed equation and to explore the effects of different charge structures on the dominant frequency *** apparent frequency proved to be more reliable to express the attenuation law of the dominant *** reliability and superiority of the proposed equation employing the apparent frequency were verified by comparison with the other five prediction *** smaller blasthole diameter or decoupling ratio leads to the higher initial value and corresponding faster attenuation of the dominant *** blasthole diameter has a greater influence on the dominant frequency attenuation than the decoupling ratio *** the charge structures applied in the experiments,the charge structure with decoupling ratio of 1.5 and blasthole diameter of 48 mm results in the greatest initial value and corresponding fastest attenuation of the dominant frequency.

关键词： Dominant frequency Blasting vibration Attenuation law Prediction equation Charge structures

On the breakage function for constructing the fragment replacement modes

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Particuology 2019年第3期17卷 207-217页

作者： Wei Zhou Kun Xu Gang Ma Xiaolin Chang State Key Laboratory of water {1. and hydropower Engineering Science Wuhan University Wuhan 430072 China Changjiang institute of Survey Planning Design and Research Wuhan 4300 W China Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering Ministry of Education Wuhan University Wuhan 430072 China

The fragment replacement method (FRM), a particle breakage simulation method, is often used in discrete element simulations to investigate the particle breakage effect on the mechanical behavior of granular materials. The fragment size distribution of the fragment replacement mode of FRM, which is generally generated based on the fragmentation characteristics of single particles after uniaxial compression, affects the breakage process and the mechanical behavior of the particle assembly. However, existing fragment replacement modes are seldom generated based on experimental data analysis. To capture the fragmentation process and investigate the breakage function for the construction of the fragment replacement mode, 60 numerical single particle compression tests were implemented by DEM. The bonded-particle model was applied to generate the crushable rock particles. The numerical simulations were qualitatively validated by experimental results, and the fragment size of broken single particles was analyzed. The fractal dimension was used to describe the fragmentation degree of single particles after compression. The fragmentation degree was random, and the fractal dimensions of the 60 tests at the same loading displacement fit the Weibull distribution well. The characteristic fractal dimension increased with increasing loading displacement, indicating that the fragmentation of single particles is a gradual process. According to the overall breakage function of the 60 tests at the first bulk breakage, a two-stage distribution model with 4 parameters was proposed and validated by the numerical and experimental results. The various fracture patterns of a single particle at the first bulk breakage under compression tests were well captured by the two-stage distribution model. Finally, an initial application strategy using the two-stage distribution model to construct fragment replacement modes was discussed and presented.

关键词： Particle breakage Single particle compression test DEM Fragment replacement mode Breakage function

Environmental DNA Assessment of Fish Diversity， Distribution and Niche Characteristics in Zhutuo Spawning Ground in the Upper Reaches of the Yangtze River

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水利水电技术(中英文) 2024年

作者： LU Jia WANG Li LI Ruijiao YANG Jin ZHANG Peng YANG Shengfa College of River & Ocean Engineering， Chongqing Jiaotong University Yangtze River Chongqing Shipping Engineering Survey and design {1. National Engineering Research Center of Inland waterway Regulation

With the implementation of the 1.-year fishing ban policy， the fish diversity and the niche characteristics of dominant species in the spawning grounds of the national Nature Reserve of rare and endemic fish in the upper reaches of the Yangtze River may change. In this study， undamaged spawning grounds of natural viscous egg-producing fish in the reserve were continuously investigated since February 2022， and the characteristics of fish species composition， biodiversity and dominant species niche were analyzed. The results showed that a total of 45 species of fish belonging to 38 genera， 1. families， and 3 orders were detected through environmental DNA （eDNA） in this survey， including 1. species endemic to the upper reaches of the Yangtze River， such as Procypris rabaudi and Myxocyprinus asiaticus. The fish community was mainly composed of bottom-dwelling， settling ovum-producing， omnivorous fish. The variation ranges of the Chao1.index， ACE index， Shannon index， and Simpson index are 736-996， 71.-965， 1.58-3.23， and 0.83-0.99， respectively， indicating that fish species in spawning sites are abundant and community distribution uniformity is high. All indexes are highest at ZT1.monitoring points. Cluster analysis showed that， at a certain similarity level， fish community types in spawning sites could be basically divided into two groups: ZT1. ZT3， and ZT5 clustered together， and ZT2 and ZT4 clustered together， indicating similar fish community habitats. There are 9 dominant fish species in typical deep pool habitats in the reserve， with niche widths (Bi) ranging from 1.1. to 3.87. The dominant fish species are broad and medium niche fish， such as Cyprinus carpio and Hemiculter tchangi， with the niche overlap index (Oik) of some dominant fish species reaching more than 0.95. This indicates fierce competition for resources among the fish in this spawning ground. This study provides a new method and perspective for fish monitoring in the upper reaches of the Yangtze Riv

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Compound extreme inundation risk of coastal wetlands caused by climate change and anthropogenic activities in the Yellow River Delta,China

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Advances in Climate Change Research 2024年第1期15卷 134-147页

作者： Xiao-Li WANG Ai-Qing FENG Xi-Yong HOU Qing-Chen CHAO Bai-Yuan SONG Yu-Bin LIU Qi-Guang WANG He XU Yu-Xin ZHANG Dong Li Li-Jie DONG Yu GUO CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation Yantai Institute of Coastal Zone ResearchChinese Academy of SciencesYantai 264003China Shandong Key Laboratory of Coastal Environmental Processes Yantai 264003China China Meteorological Administration Key Laboratory for Climate Prediction Studies National Climate CentreBeijing 100081China Tongji Urban planning {1. Research institute Shanghai 200092China School of Geography and Tourism Qilu Normal UniversityJinan 250200China China Meteorological Administration Training Centre China Meteorological AdministrationBeijing 10008China University of Chinese Academy of Sciences Beijing 100049China Marine Science and Technology College Zhejiang Ocean UniversityZhoushan 316022China

The coastal wetlands of the Yellow River Delta(YRD)in China are crucial for their valuable resources,environmental significance,and economic ***,these wetlands are also vulnerable to the dual threats of climate change and human *** substantial attention to the historical shifts in YRD's coastal wetlands,uncertainties remain regarding their future trajectory in the face of compound risks from climate change and anthropogenic *** on a range of remote sensing data sources,this study undertakes a comprehensive investigation into the evolution of YRD's coastal wetlands between 2000 and ***,the potential fate of coastal wetlands is thoroughly analyzed through the Land Use/Cover Change(LUCC)simulation using System Dynamic-Future Land Use Simulation(SD-FLUS)model and the extreme {1. levels projection integrated future sea-level rise,storm surge,and astronomical high tide in 2030,2050,and 21.0 under scenarios of SSP1.2.6,SSP2-4.5,and *** revealed that YRD's coastal wetlands underwent a marked reduction,shrinking by 1.88.72 km²from 2000 to *** decline was mostly attributed to the substantial expansion in the areas of artificial wetlands(increasing by 823.78 km2),construction land(increasing by 767.71.km²),and shallow {1.(increasing by 274.58 km²).Looking ahead to 2030-21.0,the fate of coastal wetlands appears to diverge based on different *** the SSP1.2.6 scenario,the area of coastal wetland is projected to experience considerable *** contrast,the SSP5-8.5 scenario anticipates a notable decrease in coastal *** to the inundated area suffered from the current extreme {1. levels,the study projects a decrease of 6.8%-1..6%in submerged coastal wetlands by 2030 and 9.4%-1..2%by 2050 across all *** 21.0,these percentages are projected to decrease by 0.4%(SSP2-4.5)and 27.1.(SSP5-8.5),but increase by 35.7%(SSP1.2.6).Results suggest that coastal wetlands in th

关键词： Climate change Anthropogenic activities Compound extreme risk Coastal wetlands Yellow River Delta

氮添加对内蒙古草原植物地上和地下碳氮磷化学计量学特征的影响

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Journal of Plant Ecology 2024年第1期17卷 57-67页

作者： Ziqi Wang Jie Wang Honghui Wu Tian Yang Yixin An Yunlong Zhang Jianlin Bian Ying Li Haiyan Ren Ariuntsetseg Lkhagva Xu Wang Qiang Yu School of Grassland Science Beijing Forestry UniversityBeijing 100083China National Hulunber Grassland Ecosystem Observation and Research Station Institute of Agricultural Resources and Regional PlanningChinese Academy of Agricultural SciencesBeijing 100081China Ministry of Agriculture Key Laboratory of Crop Nutrition and Fertilization Institute of Agricultural Resources and Regional PlanningChinese Academy of Agricultural SciencesBeijing 100081China Department of Biology University of Western OntarioLondonONCanada College of Grassland Science and Technology China Agricultural UniversityBeijing 100083China College of Resource Environment and Tourism Capital Normal UniversityBeijing 100048China College of Agro-grassland Science Nanjing Agricultural UniversityNanjing 210095China Department of Biology School of Arts and SciencesNational University of MongoliaUlaanbaatar 14200Mongolia

氮沉降对生态系统功能和过程具有显著影响。已有研究表明氮添加会影响植物叶片C:N:P化学计量特征。然而,氮添加对植物根系C:N:P化学计量特征影响的研究罕有报道。本论文的主要目的是对比氮添加对草原植物群落地上和地下C:N:P化学计量特... 详细信息

氮沉降对生态系统功能和过程具有显著影响。已有研究表明氮添加会影响植物叶片C:N:P化学计量特征。然而,氮添加对植物根系C:N:P化学计量特征影响的研究罕有报道。本论文的主要目的是对比氮添加对草原植物群落地上和地下C:N:P化学计量特征的影响。我们在内蒙古锡林郭勒草原开展了一个7年的氮添加实验,该实验包括6个处理,分别是对照:control;N1.0.4 mol·m-2 N;N2:0.8 mol·m^(-2) N;N3:1.6 mol·m^(-2) N;N4:2.8 mol·m^(-2) N;N5:4 mol·m^(-2) N,每个处理6次重复。我们测量并分析了植物地上、地下生物量和C:N:P化学计量特征。研究结果表明,氮添加会导致植物群落地上部分碳浓度降低,氮浓度和磷浓度升高,C:N和C:P比值降低,N:P升高,而且地上碳、氮、磷库均因施氮而增加。然而,氮添加对0-1.,1.-30,30-50和50-1.0 cm 4个土层的地下部分碳、氮、磷浓度、比例、库和化学计量特征没有显著影响。综上所述,氮添加会显著改变植物群落地上部分C:N:P化学计量特征,进而影响草地生态系统的功能和过程,但对地下C:N:P化学计量特征几乎没有影响。

关键词：氮沉降 C:N:P 化学计量草地生态系统群落地下

A 2D well-balanced, coupled model of water flow, sediment transport,and bed evolution based on unstructured grids with efficient variable storage strategy

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International Journal of Sediment Research 2021年第1期36卷 151-160页

作者： Zhiyuan Yue Qingquan Liu Wei Huang Peng Hu Zhixian Cao Department of Mechanics Beijing Institute of Technology Changjiang Survey planning {1. and Research Co. Ltd (CSPDR) Changjiang River Scientific Research institute Department of Ocean Engineering Ocean College Zhejiang University State Key Laboratory of water {1. and hydropower Engineering Science Wuhan University

In recent decades,a few Godunov-type,finite volume two-dimensional(2 D) unstructured grid,coupled flow,and sediment models(GF2 DUCM) have been developed for flows over erodible *** kinds of models are generally analyzed as a Vertex Model(VM) that define topography at the cell vertex,which can lead to the non-conservation of mass regarding flow,sediment,and bed ***,a full cellcantered variable storage method(Central Model or CM) is applied as the solution of the GF2 *** this method,terrain elevation is defined at the cell centroids;this accurately describes the physical relations between the {1. depth and topography *** approach can fully eliminate calculation errors in topography deformation at local cells caused by the interpolation of topography deformation at the cell vertex,and reduced uncertainty in the computation of the GF2 *** model performance is systematically tested using a series of laboratory experiments,which demonstrate the mass conservation feature and high accuracy in reproducing hydrodynamic and morphological processes.

关键词： Two-dimensional coupled model Well-conserved Unstructured grids Finite-volume algorithm Erodible bed Central model

Numerical simulation of two-phase turbulent flow in hydraulic and hydropower engineering

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Science China(Technological Sciences) 2007年第z1期50卷 79-89页

作者： DAI HuiChao1.2?, WANG LingLing1. GAO JiZhang3, ZHANG XiaoDong3 & YANG ZhongHua2 1.College of water Conservancy and {1. Engineering, Hohai University, Nanjing 21.098, China 2 China Yangtze River Three Gorges Project Development Corporation, Yichang 443002, China 3 China institute of water resources and {1. Research, Beijing 1.0044, China College of water Conservancy and {1. Engineering Hohai University Nanjing 210098 China China Yangtze River Three Gorges Project Development Corporation Yichang 443002 China China institute of {1. resources and hydropower Research Beijing 100044 China

In connection with the specific features of high velocity aerated flow generated by hydraulic engineering structures, the mathematical model is developed for high turbulence air-water two-phase flow with the use of twin flow theoretical model in this paper. Furthermore the numerical method is proposed to treat bubbled flows. In addition, on the basis of air-water stratified twin flow model, the new calculation methods and free surface tracking technique are proposed to describe complicated movements of the free surface. Finally, the proposed model is used to calculate artificial aerated flows. The computed results coincide quite well with experimental results. This means that the proposed method can provide solid basis for practical engineering design.

关键词： high turbulence two-phase flow twin flow model aerated flow free surface

Mechanisms of suspended sediment restoration and bed level compensation in downstream reaches of the Three Gorges Projects(TGP)

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Journal of Geographical Sciences 2017年第4期27卷 463-480页

作者：张为杨云平张明进李义天朱玲玲由星莹王冬徐俊锋 State Key Laboratory of water {1. and hydropower Engineering Science Wuhan University Key Laboratory of Engineering Sediment Tianjin Research Institute for Water Transport Engineering Ministry of Transport Bureau of Hydrology Changjiang Water Resources Commission Hubei Provincial water {1. and hydropower planning Survey and design institute Changjiang River Scientific Research institute

River basin reservoir construction affects water and sediment transport processes in downstream reaches. The downstream impact of the Three Gorges Projects （TGP） has started to become apparent：（1. reduction in flood duration and discharge, and significant reduction in sediment load. Although there was some restoration in downstream sediment load, the total amount did not exceed the pre-impoundment annual average; （2） in 2003-201. the d 〉 0.1.5 mm （coarse sand） load was restored to some degree, and to a maximum at Jianli Station, which was mainly at the pre-impoundment average. After restoration, erosion and deposition characteristics of the sediment was identical to that before impoundment. The degree of restoration during 2008-201. was less than during 2003-2007; （3） after TGP im- poundment, there was some restoration in d 〈 0.1.5 mm （fine sand） sediment load, however, it was {ower than the pre-impoundment average; （4） due to riverbed compensation, the d 〉 0.1.5 mm sediment load recovered to a certain degree after impoundment, however, the total did not exceed 4400x1.4 t/y. This was mainly limited by flood duration and the average flow rate, and was less affected by upstream main stream, tributaries, or lakes. Restoration of d 〈 0.1.5 mm suspended sediment was largely controlled by upstream main stream, tributaries, and lakes, as well as by riverbed compensation. Due to bed armoring, riverbed fine suspended sediment compensation capability was weakened; （5） during 2003-2007 and 2008-201., Yichang to Zhicheng and upper Jingjiang experienced coarse and fine erosion,lower Jingjiang experienced coarse deposition and fine erosion, Hankou to Datong had coarse deposition and fine erosion, and Chenglingji and Hankou was characterized by coarse deposition and fine sand erosion in 2003-2007, and coarse and fine erosion in 2008-201.. This difference was controlled by flood duration and number at Luoshan Station.

关键词： sediment restoration riverbed compensation TGP middle and lower reaches of the Yangtze River