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A high-order splitting scheme for the advection diffusion equation

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Journal of Environmental Sciences 2001年第4期13卷 444-448页

作者： ZHENG yong-hong shen yong-ming QIU Da-hong Guangzhou Institute of Energy Conversion the Chinese Academy of SciencesGuangzhou 510070China State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116023China

A high-order splitting scheme for the advection-diffusion equation of pollutants is proposed in this paper. The multidimensional advection-diffusion equation is splitted into several one-dimensional equations that are solved by the scheme. Only three spatial grid points are needed in each direction and the scheme has fourth-order spatial accuracy. Several typically pure advection and advection-diffusion problems are simulated. Numerical results show that the accuracy of the scheme is much higher than that of the classical schemes and the scheme can he efficiently solved with little programming effort.

关键词： pollutants advecton-diffusion equation high-order scheme numerical modelling

THREE HIGH-ORDER SPLITTING SCHEMES FOR 3D TRANSPORT EQUATION

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Applied Mathematics and Mechanics(English Edition) 2005年第8期26卷 1007-1016页

作者： WANG Shou-dong（汪守东） shen yong-ming（沈永明） State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116023 P. R. China

Two high-order splitting schemes based on the idea of the operators splitting method are given. The three-dimensional advection-diffusion equation was split into several one-dimensional equations that were solved by these two schemes, only three computational grid points were needed in each direction but the accuracy reaches the spatial fourth-order. The third scheme proposed is based on the classical ADI scheme and the accuracy of the advection term of it can reach the spatial fourth-order. Finally, two typical numerical experiments show that the solutions of these three schemes compare well with that given by the analytical solution when the Peclet number is not bigger than 5.

关键词： 3D advection and diffusion equation operator splitting method highorder scheme numerical modeling

Numerical simulation of stratified turbulent two-phase flow in aquatic environment

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Journal of Environmental Sciences 2000年第2期12卷 24-28页

作者： shen, yong-ming Wang, Ya-Ling Liang, Chuan State Key Lab. Coast. Offshore Eng. Dalian University of Technology Dalian 116023 China State Key Hydr. Lab. High Speed F. Sichuan University Chengdu 610065 China

The two fluid model of stratified turbulent two phase flow in aquatic environment is developed in this paper. The motion of each phase is described by a unified multi fluid model in an Eulerian coordinate system. The laws of turbulent transportation for each phase, and the restriction of each other between the two phases are completely simulated. The complex two phase turbulence with strong buoyancy effects is selected to examine numerically. The extensive experimental data obtained in stratified flow are used here. Comparison of the results of numerical simulation with the experimental data is conducted. It has shown that the results of numerical simulation are satisfactory.

关键词： stratified flow two phase turbulence two fluid model aquatic environment CLC number: X131 2 Document code: A

THREE-DIMENSIONAL SIMULATION OF MEANDERING RIVER BASED ON 3-D RNG k-ε TURBULENCE MODEL

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Journal of Hydrodynamics 2008年第4期20卷 448-455页

作者： ZHANG ming-liang shen yong-ming State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024China Department of Civil and Structural Engineering The Hong Kong Polytechnic University Hong Kong China

A 3-D numerical model for calculating flow in non-curvilinear coordinates was established in this article. The flow was simulated by solving the full Reynolds-averaged Navier-Stokes equations with the RNG κ-ε turbulence model. In the horizontal x-y-plane, a boundary-fitted curvilinear co-ordinate system was adopted, while in the vertical direction, a σ co-ordinate transformation was used to represent the free surface and bed topography. The water level was determined by solving the 2-D Poisson equation derived from 2-D depth averaged momentum equations. The finite-volume method was used to discretize the equations and the SIMPLEC algorithm was applied to acquire the coupling of velocity and pressure. This model was applied to simulate the meandering channels and natural rivers, and the water levels and the velocities for all sections were given. By contrasting and analyzing, the agreement with measurements is generally good. The feasibility studies of simulating flow of the natural fiver have been conducted to demonstrate its applicability to hydraulic engineering research.

关键词： non-orthogonal curvilinear coordinates RNG κ-ε turbulence model 2-D Poisson equation SIMPLEC algorithm depth averaged equation

NUMERICAL STUDY ON SALINITY STRATIFICATION IN THE OUJIANG RIVER ESTUARY

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Journal of Hydrodynamics 2009年第6期21卷 835-842页

作者： JIANG Heng-zhi shen yong-ming WANG Shou-dong State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024 China Transport Planning and Research Institute Beijing 100048 China

The variations of current, salt intrusion and vertical stratification under different conditions of river flow and wind in the Oujiang River Estuary （ORE） were investigated in this article using the Environmental Fluid Dynamics Code （EFDC）. The model was verified against water level variation, velocity, and salinity variations in June 2005. The simulation results agreed well with measured data. Six sensitivity tests were conducted for different conditions of river flow and wind specified in the model. Model results show that salinity intrudes further upstream under scenarios with low flow and downriver local wind conditions. In contrast, the responses of salinity stratification to different environmental forcing functions were different in different portions of the estuary. Salinity stratification was enhanced under high flow condition. Model results also show that wind is not crucial to the salt intrusion and salinity stratification in the ORE.

关键词： salinity stratification wind river discharge Oujiang River Estuary(ORE)

DEVELOPMENT AND APPLICATION OF A EUTROPHICATION WATER QUALITY MODEL FOR RIVER NETWORKS

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Journal of Hydrodynamics 2008年第6期20卷 719-726页

作者： ZHANG ming-liang shen yong-ming GUO Yakun State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116023 China Department of Civil and Structural Engineering The Hong Kong Polytechnic University Hong Kong China Department of Engineering University of Aberdeen Aberdeen AB24 3UE UK

The Preissmann implicit scheme was used to discretize the one-dimensional Saint-Venant equations, the river-junction-fiver method was applied to resolve the hydrodynamic and water quality model for river networks, and the key issues on the model were expatiated particularly in this article. This water quality module was designed to compute time dependent concentrations of a series of constituents, which are primarily governed by the processes of advection, dispersion and chemical reactions. Based on the theory of Water Quality Analysis Simulation Program （WASP） water quality model, emphasis was given to the simulation of the biogeochemical transformations that determine the fate of nutrients, in particular, the simulation of the aquatic cycles of nitrogen and phosphorus compounds. This model also includes procedures for the determination of growth and death of phytoplankton. This hydrodynamic and water quality model was applied to calculate two river networks. As illustrated by the numerical examples, the calculated water level and discharge agree with the measured data and the simulated trends and magnitudes of water quality constituents are generally in good agreement with field observations. It is concluded that the presented model is useful in the pollutant control and in the determination of pollutant-related problems for river networks.

关键词： Preissmann implicit scheme river networks hydrodynamic model water quality model biogeochemical transformations three-step method

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

THE TURBULENT MODEL OF LIQUID-PARTICLE FLOWS AND ITS APPLICATION TO NUMERICAL PREDICTION OF OIL POLLUTION

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Journal of Hydrodynamics 1992年第2期4卷 72-78页

作者： shen yong-ming Zhao Wen-qian, Dalian University of Technology, Dalian 116023, P. R. China Dalian Univ of Technology Dalian China

Simulation of particle turbulent transport in present mathematical models of two- phase turbulent flows is algebraic model based on local following theory. The predicted results by these models are not consistent with that of experiments available. The motion of two-phase flow is described by a unified model of multi-fluid in this paper. The two-fluid turbulent model of two-phase flow based on k-e equations for particles and fluid, and corresponding numerical thch- nique are both developed. The proposed model and the numerical technique are successfully em- ployed to numerical modelling for oil-water two-phase turbulent recirculating flow.

关键词： liquid-particle flows particle turbulence oil pollution

Impact of Sediment Supply on Spartina Salt Marshes

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Pedosphere 2008年第5期18卷 593-598页

作者： shen yong-ming YANG Jing-Song WANG Yan-Hong FENG Nian-Hua ZHOU Qin ZENG Hua Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 （China）. Department of Geography Nanjing Xiaozhuang College Nanjing 210097 （China） River and Harbor Engineering Department Nanjing Hydraulic Research Institute Nanjing 210024 （China）

During the past century,natural and human modifications of environmental systems have greatly accelerated coastal salt marsh deterioration and shoreline retreat in many regions worldwide. Field investigation,profile analysis,geographical information analysis,and remote sensing were employed in combination to study the effect of sediment on Spartina alterniflora salt marshes of the coast in Jiangsu Province,East China. The results indicated that the propagation of Spartina alterniflora salt marshes was closely related to regional sediment conditions,especially the supply of fine-grained materials. Additionally,because of the dense and high grass in Spartina alterniflora salt marshes,wave energy and tidal currents were baffled and weaker than those of the adjacent,unvegetated mud flats. Fine sediment was hardly resuspended under the low energy conditions in the Spartina alterniflora salt marshes.

关键词： cost salt marsh sediment supply Spartina alterniflora tidal mud flat