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STUDY OF THE IMPACT OF WEIRS ON CHANNEL SCOUR AND DEPOSITION

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STUDY OF THE IMPACT OF WEIRS ON CHANNEL SCOUR AND DEPOSITION

第九次河流泥沙国际学术大会

作者： Chien-Hsin LAI Management Division Water Resources Water Resources Agency Taiwan ChinaYu-Hsiung HSUConstruction and Disaster Prevention Research Center Fenchia University Taichung 407 Taiwan China (Corresponding Author) Hong-Pu HUANG Management Division Water Resources Water Resources Agency Taiwan ChinaFeng-Rong YANG Southern Region Water Resources Office Water Resources Agency Taiwan China.

＜正＞This research utilizes a quasi-two-dimensional sediment transport model to simulate the variations in sediment transport characteristics of the Nankan creek. By specifying a sediment-laden inflow to the study reach, we investigate the long-term and short-term hydraulical variations and the characteristics of sediment scour and deposition in the vicinity of cross-channel structures, such as the weirs in the Nankan creek, under given peak-flood discharges and flood hydrographs at different recurrence intervals. It is hoped that this research can enable us to better understand the hydraulic variations and characteristics of sediment scour and deposition in the upstream as well as downstream in a natural channel, and the morphological changes in channel bed after a weir is installed. The result can serve as recommendations to irrigation water management and flood control assessment.

关键词： sediment transport Morphological changes Channel bed

Finite dispersal of a divergent nepheloid plume by internal hydraulic jump in a tropical mountainous river estuary

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Finite dispersal of a divergent nepheloid plume by internal ...

第九届全国河口海岸学术研讨会

作者： Jiaxue Wu Slate Key Laboratory of Marine Geology,Tongji University, Shanghai 200092, China.

Field investigations were presented into a tropical mountainous river estuary of Herbert, Australia, following a moderate flood event induced by Cyclone Fritz. In-situ mooring and shipboard measurements were conducted using an acoustic Doppler current profiler, a conductivity-temperature-depth unit, and an optical backscatter nephelometer. Owing to the flood discharge onto the shelf, a river plume forms and is deflected under the along-shelf current induced by the trade wind. Intense stratification at the base of plume suppresses vertical mixing, significantly decreases bottom stresses, and separates the water column into two mixed layers. The normal depth of the plume relative to its critical depth is controlled only by the bed slope and the drag coefficient of the interface, independent of river discharge and buoyancy anomaly. A divergent nepheloid dispersal system usually occurs under combined flow segregation and intense stratification. Two nepheloid layers are both confined to the inner shelf under different dispersal mechanisms. The upper nepheloid layer, primarily controlled by advection and settling, is exponentially decayed away from the river mouth. The lower nepheloid layer dominated by settling is detached seaward near the lift-off point. The plume lift-off and subsequent internal jump are crucial processes for the trapping of the plume sediment because a substantial loss of energy occurs, and farther control the pattern of mud deposit on the shelf. Fronts have important influences on the sediment release from the river plume, with different trapping effect in the presence and absence of stratification.

关键词： river plume sediment transport tropical estuary internal hydraulic jump estuarine fronts

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强混合河口中沉速对高含沙区形成的作用

热带地貌 1988年第1期 63-78页

作者：吴超羽

瓯江河口存在—最大混浊带.本文根据实测含沙量和水流资料计算了由于絮凝作用而引起的沉速的沿程变化并推导出沉速和悬移质沉积物搬运的关系式.由本文提出的关系,解释了由于沉速沿程增加,引起悬移质搬运能力降低而引起悬移质积聚,这是... 详细信息

瓯江河口存在—最大混浊带.本文根据实测含沙量和水流资料计算了由于絮凝作用而引起的沉速的沿程变化并推导出沉速和悬移质沉积物搬运的关系式.由本文提出的关系,解释了由于沉速沿程增加,引起悬移质搬运能力降低而引起悬移质积聚,这是强混合河口中高含沙区形成的可能机制之一.

关键词： turbidity maximum flocculation sediment transport sediment concentration numerical model tidal estuaries salinity China coast

Dynamics Characteristics and Topographic Profile Shaping Process of Feiyan Shoal at the Yellow River Delta

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Marine Science Bulletin 2008年第2期10卷 74-88页

作者：应铭李九发陈沈良戴志军中交上海航道勘察设计研究院有限公司上海200120 华东师范大学河口海岸学国家重点实验室上海200062

Feiyan Shoal is a sub Yellow River Delta, which was formed from Jan. 1964 to May 1976, when the Yellow River entered sea via Diaokou Channel. Since the terminal reach shifted to Qingshuigou channel in 1976, Feiyan Shoal has been experiencing severe erosion and retreat. This paper explains the evolutionary characteristics of the typical profile of Feiyan Shoal from the perspective of dynamical force and sediments＇ characteristics. All this is on the basis of the data of topographic profiles observed since the 1970s and the samples of hydrology and sediments collected in situ in Apr. 2004, the analysis of the retreating distance, and the tidal and wave friction velocity distribution. Feiyan Shoal topographical profile has experienced a course of ＂fast erosion and retrogression - slow eroding modulation - fluctuate triggering change＂ in recent 30 years, which is also the gradual disappearing process of the delta front. The different intensity of sediment erosion resistance is the main reason for the erosion speed changes. Due to the hydrodynamic force changes, the water depth range of maximum retreating distance and between erosion and progradation became shallow. It indicates that the storm tide will still be the triggering force of seashore topographic profile evolutions in the future.

关键词： The Yellow River Delta Feiyan Shoal erosion wave and tidal co-action topographic profile sediment transport

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泥沙运动的动力学理论(英文)

泥沙运动的动力学理论(英文)

2009水资源与可持续发展高层论坛

作者： Guangqian Wang and Deyu Zhong 1 PhD,Prof.,the State key laboratory of Hydroscience and Engineering,Tsinghua Univ.,Beijing 100084, China. 2 PhD,Assoc.Prof.,the State key laboratory of Hydroscience and Engineering,Tsinghua Univ.,Beijing 100084,China.

＜正＞sediment transport in fluvial systems attracts considerable attention in last *** influences on river engineering,ecological systems and environment have made it one of the most important themes in modem science and ***,because of the complexity involved in sediment transport,unified theory for sediment transport has not been *** present state of the art in sediment transport has imposed considerable limitation for us on further studies of sediment transport and related *** in this paper is a brief introduction to the kinetic theory for sediment *** general features of the kinetic theory for sediment transport are *** kinetic equation is solved for velocity distribution function of sediment moving in turbulent open channel flow to obtain the transport properties of sediment *** vertical concentration profile of suspended load and bed-load transport rate are investigated in this paper as the examples of the applications of the *** shows satisfactory agreement between the theory and observation,which indicate that the kinetic theory is a promising analytical framework in the study of sediment transport,and expected to be the theory that provides more unified description of sediment transport,the most complicated transport phenomena in nature.

关键词： Kinetic theory sediment transport Suspended load Bed load.

Unit stream power,minimum energy dissipation rate,and river engineering

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水道港口 2010年第5期31卷 317-317页

作者： Chih Ted Yang Civil and Environmental Engineering Department Colorado State University

Unit stream power is the most important and dominant parameter for the determination of transport rate of sand,gravel,and hyper-concentrated sediment with wash *** energy dissipation rate theory,or its simplified minimum unit stream power and minimum stream power theories,can provide engineers the needed theoretical basis for river morphology and river engineering *** Generalized sediment transport model for Alluvial River Simulation computer mode series have been developed based on the above *** computer model series have been successfully applied in many *** will be used to illustrate the applications of the computer models to solving a wide range of river morphology and river engineering problems.

关键词： computer model minimum energy dissipation rate river engineering river morphology sediment transport unit stream power

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Local scour at submarine pipelines

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水道港口 2010年第5期31卷 322-322页

作者： Yee-Meng Chiew School of Civil and Environmental Engineering Nanyang Technological University

The rapid development of offshore oilfields has increased the number of submarine pipelines being constructed for the transport of crude oil to onshore *** between the pipeline and an erodible bed under the influence of current and waves often lead to local scouring around the *** this occurs, the pipeline may be suspended on the seabed resulting in the formation of a *** the free span is long enough, the pipe may experience resonant flow-induced oscillations,leading to structural *** study examines the complex flow-structure-sediment interaction leading to the development of local scour holes around submarine *** reviews published literature in this area,which primarily is confined to the development of 2- dimensional scour *** the abundance of such research studies,pipeline-scour in the field essentially is 3-dimensional in ***,most of these studies have overlooked the importance of the transverse dimension of the scour hole,while emphasizing on its vertical *** clearly is an issue that must be re-examined in light of the potential hazard and environmental disaster that one faces in the event of a pipeline *** studies have begun to recognize this shortcoming,and attempts have been made to overcome the *** study presents the state-of-the-art knowledge on local scour at submarine pipelines,both from a 2-dimensional as well as the 3-dimensional perspective.

关键词： scour sediment transport submarine pipeline offshore pipelines

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