检索结果-南通市图书馆

Dimension and frequency of bar formation in a braided river

在线全文

学校读者我要写书评

暂无评论

International Journal of Sediment Research 2013年第3期28卷 358-367页

作者： Hsuan-pei AN Su-chin CHEN Hsun-chuan CHAN Yi HSU Department of Soil and Water Conservation National ChungHsing University

This paper presents flume and field observations of a bank-confined braided *** features,including plan form configuration,channel width,and main channel migration,were examined by a series of *** measurements of channel morphology,provided a basis to estimate the relationship between noncumulative frequency of bars and bar *** results from the Dajia river,located in Central Western Taiwan,were presented to provide a reference data set for comparing the laboratory and field *** results indicate that the relationship between bar length and width can be predicted by a simple best-fit power function relating to self-similarity *** Hurst index by Walsh and Hicks(2002) provides acceptable predictions of the bar length and width observed in the experiments and confirmed by the field *** and field results both show that large river width yields a uniform distribution of bar areas with the similar discharge,leading to a large value of exponent(ft) in the *** river width is confirmed to be a critical parameter in the main channel shift.A small increase in channel width likely increased rapidly the shift cycle.

关键词： braided river Bank confinement Bar morphology

Study on the Distribution of Interlayer in Thick Sandy braided river under Large Well Spacing—A Case of C Oilfield in Bohai Sea

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Geology 2022年第6期12卷 460-471页

作者： Wentong Zhang Bo Quan Songru Mu Jie Tan Qing Zhou Bohai Oilfield Research Institute CNOOC Ltd. Tianjin China

Using core, logging and other data, combined with field outcrop deposition, this paper studies the sedimentary genetic types and sedimentary stages of thick sandy braided river interlayer in C oilfield, and divides two stages of interlayer and three single-stage braided flow zones. On this basis, geostatistical inversion constrained by logging and discerning river quantitative knowledge base is carried out to predict the distribution range of the main interlayer in the two phases. The production performance test of the blind well and horizontal well shows that the coincidence rate of the prediction results of interlayer with thickness > 1.5 m is 75%. The research shows that the first stage is the main interlayer, mainly composed of mudstone of flood plain origin, with an average thickness of 2.1 m and relatively stable distribution. Based on the interlayer prediction results, the small layer of composite sand body 1 forms a residual oil enrichment area in the high part of the structure due to the wide range of interlayer shielding in the lower part, which is a favorable area for adjusting and tapping potential.

关键词： Bohai Oilfield braided river Horizontal Well Geostatistical Inversion Interlayer Prediction

EXPERIMENTS OF THREE-DIMENSIONAL FLOW STRUCTURE IN braided riverS

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2009年第2期21卷 228-237页

作者： HUA Zu-lin GU Li CHU Ke-jian Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education College of Environmental Science and Engineering Hohai University Nanjing 210098 China State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai University Nanjing210098 China

The braided river is a typical river pattern in nature, but there is a paucity of comprehensive data set describing the three-dimensional flow field in the braided river. A physical model experiment was used to study the flow characteristics in the typical braided river with a mid-bar between two anabranches. In the experiment, two kinds of mid-bar with the ratios of its length to maximal width of 3 and 5 were considered. Moreover, the mid-bar could be moved to adjust the width of two anabranches. The detailed measurements of velocity were conducted using an acoustic Doppler velocimeter over a grid defined throughout the whole braided river region, including the bifurcation, two anabranches and the confluence. In two kinds of mid-bar braided models, a separation zone was observed in the anabranch of the model in which the ratio of length to maximal width of mid-bar is 3, however the separation zone was not found in another model in which the ratio is 5. In addition, the opposite secondary cells were observed at the bend apex of anabranch in two models, and different longitudinal velocity distributions in the entrance region of anabranch account for this opposite flow structure. Finally, turbulent kinetic energy were shown and compared in different situations. The high turbulence occurs at the place with strong shear, especially at the boundary of the separation zone and the high velocity passing flow.

关键词： braided river three-dimensional flow structure secondary flow turbulent kinetic energy

Impacts of dams and land-use changes on hydromorphology of braided channels in the Lhasa river of the Qinghai-Tibet Plateau,China

在线全文

学校读者我要写书评

暂无评论

International Journal of Sediment Research 2022年第2期37卷 214-228页

作者： Yuchi You Zhiwei Li Peng Gao Tiesong Hu School of Hydraulic Engineering Changsha University of Science & Technology State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Department of Geography and the Environment Syracuse University

Among braided rivers developed on the Qinghai-Tibet Plateau of China at very high elevations(>3,500 m),the middle and lower reaches of the Lhasa river have been affected by comprehensive human activities mainly involving dam construction,urbanization,farming,afforestation,and *** the current study,the impacts of these human activities on hydrology and morphology of the four braided reaches downstream of a cascaded of two dams are *** study period was divided into 1985-2006(P1),2006-2013(P2),and 2013-2019(P3),representing the natural and changed flow regimes by *** available daily discharge data at two stations within the four braided reaches,dam-induced hydrological alteration was analyzed based on the indicators of hydrologic alteration and range of variability approach and key discharge proxies were *** sensed images also were selected in the three periods and morphological metrics extracted from them were compared for the four reaches among these *** hydrological regimes were found for only two *** total channel width(Wc) and braiding intensity(BIt) followed different temporal trends among the four *** average shift rates of the main channel in the four reaches were higher in the short(P2-P3) than in the long(P1-P2 and P1-P3) *** longitudinal changes of Wcand the number of channels did not have any identifiable trend among the four *** linking the morphological changes to quantified spatial and temporal patterns of various human activities,it was found that(1) the two dams had insignificant impact on channel morphology,suggesting that the studied braided river might have a short relaxation time and(2) the evolutional trajectories of morphological changes in most of the four reaches were similar,suggesting that temporal trends of morphological changes due to complex human activities are not affected by the different physiographic settings of the *** exploitati

关键词： braided river Channel morphology Human activities Dam impact

EVOLUTIONAL CHARACTERISTICS OF HYPER－CONCENTRATED FLOW IN braided CHANNEL OF THE YELLOW river

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

International Journal of Sediment Research 1996年第3期 49-57页

作者： QI Pu LI Wenxue( Institute of Hydraulic Research,Yellow river Conservancy Commission,Zhengzhou 450003,P.R.China)( Chief Engineer,Yellow river Conservancy Commission,Zhengzhou 450003,P.R.China)

ＥＶＯＬＵＴＩＯＮＡＬＣＨＡＲＡＣＴＥＲＩＳＴＩＣＳＯＦＨＹＰＥＲ－ＣＯＮＣＥＮＴＲＡＴＥＤＦＬＯＷＩＮＢＲＡＩＤＥＤＣＨＡＮＮＥＬＯＦＴＨＥＹＥＬＬＯＷＲＩＶＥＲ￥ＱＩＰｕ；ＬＩＷｅｎｘｕｅ（Ｓｅｎｉｏｒｅｎｇｉｎ... 详细信息

ＥＶＯＬＵＴＩＯＮＡＬＣＨＡＲＡＣＴＥＲＩＳＴＩＣＳＯＦＨＹＰＥＲ－ＣＯＮＣＥＮＴＲＡＴＥＤＦＬＯＷＩＮＢＲＡＩＤＥＤＣＨＡＮＮＥＬＯＦＴＨＥＹＥＬＬＯＷＲＩＶＥＲ￥ＱＩＰｕ；ＬＩＷｅｎｘｕｅ（Ｓｅｎｉｏｒｅｎｇｉｎｅｅｒ，ＩｎｓｔｉｔｕｔｅｏｆＨｙ...

关键词： Hyper-concentrated flood Channel braided river Hydrograph Sediment concentration Peak flow Flood stage Channel shape

Seismic Sedimentology and Its Application in Shallow Sea Area,Gentle Slope Belt of Chengning Uplift

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Earth Science 2010年第4期21卷 471-479页

作者：张宪国林承焰张涛 Georesource and Information College China University of Petroleum(Dongying)

Seismic sedimentology is a new frontier inter-discipline subject, and shows good prospect and potentiality in reservoir deposition research with seismic data and geophysics technologies. We made seismic sedimentology research of shallow sea area, gentle slope belt of Chengning （埕宁） uplift, Bohalwan （渤海湾） basin. In shallow sea area with sparse well coverage, it was difficult to characterize the reservoir architecture with the traditional method based on wells. A new method to resolve the above problems is built：（1） information on plane and in section is inter-ealibrated with each other; （2） recognize the isochronic surfaces by frequency decomposition and interpret the depositional character with technology of stratal slicing; （3） make a comprehensive research with the stratal slice interpreta- tion and the dissection of well group. The depositional model of this area is built and used in the architecture analysis of area without wells. The architecture description reveals that the sedimentary character of pan-connection sand bodies in braided rivers is the reason for high water cut of the new horizontal wells. .

关键词： seismic sedimentology shallow sea area gentle slope belt of Chenguing uplift braided river architecture braided bar

A new 'superassemblage' model explaining proximal-to-distal and lateral facies changes in fluvial environments,based on the Proterozoic Sanjauli Formation(Lesser Himalaya,India)

在线全文

学校读者我要写书评

暂无评论

Journal of Palaeogeography 2016年第4期5卷 391-408页

作者： Ananya Mukhopadhyay Priyanka Mazumdar A.J. (Tom) van Loon Department of Earth Sciences Indian Institute of Engineering Science & Technology Shibpur Howrah West Bengal 711103 India Geocom Consulting Valle del Portet 17 03726 Benitachell Spain

Facies analysis of fluvial deposits of the Proterozoic Sanjauli Formation in the Lesser Himalaya was combined with an architectural analysis. On this basis, a model was developed that may be applied to other fluvial systems as well, whether old or recent. The new model, which might be considered as an assemblage of previous models, explains lateral variations in architecture and facies but is not in all respects consistent with the standard fluvial models. The Sanjauli fluvial model is unique in that it deals with lateral facies variations due to shifts of the base-level along with fluctuations in accommodation space owing to changes in palaeoclimate.

关键词： Ftuvial model braided river Sanjauli Formation Simta Basin Proterozoic Lesser Himalaya India

Analysis of controls upon channel planform at the First Great Bend of the Upper Yellow river, Qinghai-Tibet Plateau

在线全文

学校读者我要写书评

暂无评论

Journal of Geographical Sciences 2013年第5期23卷 833-848页

作者： LI Zhiwei WANG Zhaoyin PAN Baozhu DU Jun Gary BRIERLEY YU Guo-an Brendon BLUE State Key Laboratory of Hydroscience and Engineering Tsinghua University Beijing 100084 China Changjiang river Scientific Research Institute Wuhan 430010 China School of Environment University of Auckland Private Bag 92019 Auckland New Zealand Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources Research CAS Beijing 100101 China

The 270 km long section of the Upper Yellow river at the First Great Bend is comprised of single channel and multiple channel systems that alternate among anastomosing, anabranching, meandering and braided reaches. The sequence of downstream pattern changes is characterized as： anastomosing-anabranching, anabranching-meandering, meandering-braided and braided-meandering. Remote sensing images, DEM data and field investigations are used to assess ahd interpret controls on these reach transitions. Channel slope and bed sediment size are key determinants of transitions in channel planform. Anas- tomosing reaches have a relatively high bed slope （0.86‰） and coarser sediment bed material （d50 = 3.5 mm）. In contrast, meandering reaches have a low slope （0.30‰） and fine sediment bed material （d50 = 0.036 mm）. The transition from a meandering to braided pattern is characterized by an increase in channel width-depth ratio, indicating the important role of bank strength （i.e. cohesive versus non-cohesive versus channel boundaries）. Interestingly, the braided-meandering and meandering-braided transitions are coincident with variable flow inputs from tributary rivers （Baihe and Heihe rivers respectively）. Theoretical analysis of the meandering-braided transition highlights the key control of channel width-depth ratio as a determinant of channel planform.

关键词： Yellow river Source river pattern diversity river pattern transition anastomosing river ana- branching river meandering river braided river