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A three dimensional k-ε-Ap model for water-sediment movement

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International Journal of Sediment research 2010年第1期25卷 17-27页

作者： LIU Cheng1 and SHEN Yong-Ming2 1Ph.D.,pearl river hydraulic research institute,guangzhou,510611,china 2Prof.,State Key Laboratory of Coastal and Offshore Engineering,Dalian University of Technology,Dalian 116024,china Ph.D. Pearl River Hydraulic Research Institute Guangzhou 510611 China Prof. State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024 China

A three-dimensional k-ε-Ap two-fluid turbulence model is proposed to study liquid-particle two-phase flow and bed deformation. By solving coupled liquid-phase and solid-phase governing equations in a finite-volume method, the model can calculate the movement of both water and sediment. The model was validated by water-sediment transport in a 180° channel bend with a movable bed. The validation concerns two-phase time-averaged velocities, bed deformation, water depth, depth-averaged streamwise velocity, cross-stream bed profiles, and two-phase secondary flow velocity vectors. The agreement between numerical results and experimental results was generally good. The comparisons of the numerical results of different models show that the three-dimensional k-ε-Ap two-fluid turbulence model has a relatively higher accuracy than one-fluid model.

关键词： Three dimensional k-ε-Ap model Liquid-particle flow Two-fluid model Channel bend Bed deformation Curvilinear coordinates

The organic geochemistry of crude oil in the Saltpond Basin(Ghana):Organic source input,depositional environment,and thermal maturity

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Acta Geochimica 2024年第3期43卷 424-440页

作者： Kojo Amoako Ningning Zhong Nancy pearl Osei-Boakye Ebenezer Apesegah research Group for Marine Geochemistry(ICBM-MPI Bridging Group) Institute for Chemistry and Biology of the Marine Environment(ICBM)School of Mathematics and ScienceCarl von Ossietzky UniversitäOldenburgAmmerläder HeerstraВ114-11826129 OldenburgGermany State Key Laboratory of Petroleum Resources and Prospecting College of GeosciencesChina University of PetroleumBeijing 102249China Petroleum Corporation GNPCPMBPetroleum HouseTemaGhana

The Saltpond Basin,situated within the South Atlantic margin of Ghana,is a significant area for petro-leum exploration but has received relatively limited research *** studies have examined source rock com-position,but data on crude oil organic chemistry are lack-ing,hindering understanding of the basin’s petroleum system and *** address this gap,we analyzed biomarkers and stable carbon-isotope ratios in Saltpond Basin crude oil using gas chromatography–mass spectrometry and gas chromatography–isotope ratio mass spectrometry to eluci-date organic matter source,depositional environment,and thermal *** were compared with oils from the West African segment of the South Atlantic margin,namely the Tano Basin and the Niger Delta Basin,to iden-tify potential correlations and gain insights into regional *** and isotopic results unveiled a sig-nificant prevalence of organic matter derived from lower marine *** of organic matter deposition and preservation in Saltpond oil samples suggested a suboxic marine transitional environment,contradicting conventional understanding of terrestrial dominance in such ***,the potential for degradation processes to obscure differentiation between terrestrial and marine organic mat-ter origins underscores the complex nature of organic mat-ter dynamics in transitional marine *** of molecular thermal maturity indices suggested Saltpond oils were expelled from source rocks exhibiting thermal maturity at the early maturity *** analysis unveiled genetic disparities among crude oils sourced from the Saltpond Basin and those from the Tano and Niger Delta Basin,primarily due to variations in source input and depo-sitional environment *** oil exhibits lower terrestrial organic input than Tano Basin’s crude oils,which also have less terrestrial input than Niger Delta Basin crude ***,its paleodepositional envi

关键词： Biomarkers Carbon isotopes Crude oil Saltpond Basin Ghana

EXPERIMENTAL INVESTIGATION OF EFFECT OF TIDE ON COASTAL GROUNDWATER TABLE

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Journal of Hydrodynamics 2010年第1期22卷 66-72页

作者： WU Longohua ZHUANG Shui-ying Center for Eco-Environmental Modeling Hohai University Nanjing 210098 China pearl river Water Resources Scientific research institute Guangzhou 510611 China

In this article, a tide simulation system based on a two-way water pump technique is developed. Using this system and numerical simulations, the groundwater table fluctuation characteristics, relative over height of groundwater table, and influencing factors of over height are investigated. The experimental and numerical results indicate that the groundwater table fluctuation is of periodic, and of asymmetric. The amplitude of groundwater table fluctuations decreases with the increase of the onshore distances. There are phase lags of groundwater table fluctuations for different monitoring points. The tide can bring about remarkable over height of coastal groundwater table. The dominating factors bring about over height include the tide amplitude, aquifer thickness and tide frequency. Under experimental conditions, the relative tide amplitude over height may exceeded 50% of the maximal tide amplitude, and reach about 10% of aquifer thickness.

关键词： tide simulation system coastal aquifer groundwater table over height

FLOW STRUCTURE AND SEDIMENT TRANSPORT WITH IMPACTS OF AQUATIC VEGETATION

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Journal of Hydrodynamics 2008年第4期20卷 461-468页

作者： LIU Cheng SHEN Yong-ming pearl river hydraulic research institute Guangzhou 510611 China State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116023 China State Key L-aborat-ory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116023China

Aquatic vegetation plays an important role in the flow structure of open channels and thus changes the fate and the transport of sediment. This article proposes a three-dimensional turbulence model by introducing vegetation density and drag force into the control equations of water flow in the presence of vegetation. The model was used to calculate the impacts of submerged vegetation on the vertical profiles of longitudinal flow velocities, the changes of the depth-averaged flow velocities in a compound channel with emergent vegetation in the floodplain, the removal of suspended sediment from the channels by emergent vegetation, and the bed changes around and in a vegetated island. Numerical investigations show that aquatic vegetation retards flow in the vegetation zone, reduces the sediment transport capacity, and contributes to erosion on both sides of the vegetated island. Calculated results agree well with experimental results.

关键词： three-dimensional turbulence model aquatic vegetation flow structure sediment transport suspended sediment bed surface topography change

RECIRCULATING FLOW IN SHALLOW OPEN CHANNEL via THE RNG κ-ε MODEL

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Journal of Hydrodynamics 1999年第1期11卷 41-49页

作者： Kuang Cui-ping (Department of river & Harbour Engineering, Nanjing hydraulic research institute, Nanjing 210024, P. R. china ) Nanjing hydraulic research Inst Nanjing China

The steady recirculating flow behind a sudden expansion in a shallow channel is studied using the renormalization group (RNG) κ-ε model. The predicted recirculating flow and the reattachment length of the recirculating flow are well-supported by the reported experimental data. The computed effective viscosity, turbulence kinetic energy and its dissipation rate given by the RNG κ-ε model are smaller than that by the standard κ-ε model, while the reattachment length of the recirculating flow is larger. The RNG κ-ε medel overcomes the shortcoming of underpredicting the length of the recirculation zone by the standard κ-ε model.

关键词： open channel RNG κ-ε recirculating flow

On geo-basis of river regulation——A case study for the middle reaches of the Yangtze river

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Science china(Technological Sciences) 2008年第5期51卷 494-505页

作者： LIU GuoWei Nanjing hydraulic research institute, Nanjing 210029, china Nanjing hydraulic research institute Nanjing China

From the point of view that people have to obey the river's geo-attributes in the river regulation, the definition and the meaning of the geo-attributes of a river are discussed. The geo-basis of the river regulation of the middle reaches of the Yangtze river is expounded in five aspects, including the structural geomorphology environment of flood storage and discharge, the distribution characteristics of subsidence and the sedimentation areas of Dongting Basin, the history evolution of Jianghan Basin, the function of Jianghan Basin and Dongting Basin as the flood water detention areas of Jingjiang river reach in ancient time, and the geological characteristic of Jingjiang river reach. Based on the geo-attributes of the middle reaches of the Yangtze river, some ideas about the middle reach regulation of the Yangtze river are put forward: to process the interchange between the lakes and diked marsh areas in Dongting Basin, to canal the new river route as the flood diversion channel of Jingjiang river reach with the paleo river, to recover the function of Jianghan Basin as flood detention area of the middle reaches. And we should take into consideration the geo-environment of the whole Yangtze river in the river regulation of middle reaches.

关键词： river geo-attributes river regulation the Yangtze river flood

Velocity and pressure distributions in discharge tunnel of rotary-obstruction composite inner energy dissipation

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Science china(Technological Sciences) 2011年第S1期54卷 111-117页

作者： CAO ShuangLi 1,NIU ZhengMing 1,YANG Jian 2 & LU HongBo 1 1 Xi’an University of Technology,Xi’an 710048,china 2 china Water Resources pearl river Planning,Surveying & Designing Co.Ltd,guangzhou 510610,china Xi’an University of Technology Xi’an China china Water Resources pearl river Planning Surveying & Designing Co. Ltd Guangzhou China

On the basis of model test and theoretical analysis of velocity and pressure distributions,an hypothesis is presented that the distribution of tangential velocity in radial direction seems to be a combinational distribution of a quasi-free vortex and a quasi-forced vortex for the discharge tunnel of rotary-obstruction composite inner energy *** variations of corresponding parameters about the hypothesis are obtained under test conditions in this *** formula of pressure distribution in radial direction is deduced theoretically,and the theoretical values of pressure distribution computed by the formula are well consistent with the measured ones,showing that the formula is correct and can be applied to the computation and analysis of pressure distribution of this discharge tunnel.

关键词： discharge tunnel rotary-obstruction composite inner energy dissipater model test assumption of velocity distribution the formula of pressure distribution

DISTRIBUTION OF BIOAVAILABLE PHOSPHORUS BETWEEN OVERLYING WATER AND SPM UNDER ABRUPT EXPANSION CONDITION

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Journal of Hydrodynamics 2011年第3期23卷 398-406页

作者： WAN Jun WANG Ze QIAN Shu-qin College of Water Conservancy and Hydropower Engineering Hohai University Nanjing 210098 China College of Mechanics and Materials Hohai University Nanjing 210098 China institute of pearl river Water research Guangzhou 510611 China

Experiments on Phosphorus （P） fraction characteristics in sediment resuspension were performed under adequate hydrodynamic conditions. It is found that the concentration of Suspended Particulate Matter （SPM） in the eddy current region exhibits the ＂Matthew effect＂. Velocity is an impact factor of the Equilibrium Phosphate Concentration （EPC）, which is related to other hydraulic conditions. Overall bioavailable dissolved P in the SPM causes migration to overlying water and sediment, eventually being converted into a chemical speciation of P. Conditions of resuspension promote A1-P of SPM that migrated to the sediment and water. Concentrations of A1-P in SPM are reduced. P is released from SPM to water bodies, mainly through conversion into particulate P and dissolved total P. Meanwhile, exchange between SPM and sediments occur mainly through Ca-P migration. A1-P and BD-P possess similar geochemical characteristics or source. Ca-P and A1-P exhibit a negative correlation between migration and conversion.

关键词： bioavailable phosphorus Suspended Particulate Matter (SPM) abrupt expansion flow resuspension

Response of flood discharging capacity to the deterioration of the lower Yellow river

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Science china(Technological Sciences) 2004年第Z1期47卷 152-160页

作者： LI Wenxue1, LI Yong2, YAO Wenyi2, SU Yunqi2 & ZHANG Xiaohua2 1. Yellow river Engineering Consulting Co. Ltd., Zhengzhou 450003, china 2. Yellow river institute of hydraulic research, Zhengzhou 450003, china Yellow river Engineering Consulting Co. Ltd. Zhengzhou China Yellow river institute of hydraulic research Zhengzhou China

Based on the clarifications of the deterioration characteristics of the lower Yellow river (LYR), the influence of river deterioration on flood discharging capacity is studied through theoretical derivation and analysis of field data. This study indicates that response of flood discharging capacity to river deterioration is nonlinear. Sediment depositions in the main channel cause the reductions of dominant discharge and thus the increase of initial flood stage. Reductions in the channel width result in the increases of the rising rate of flood stage and the decrease of flood discharging capacity.

关键词： flood discharging capacity, boundary condition, deterioration, sediment, the lower Yellow river.