NUMERICAL SIMULATION OF 2-D TIDAL FLOW AND WATER QUALITY UNDER THE CURVILINEAR COORDINATES

This paper presents a numerical method to simulate the 2-D tidal flow and water quality under the curvilinear coordinates. In order to overcome the computational difficulties in natural rivers, such as the complicated boundary figures, the great disparity between length and width of computational domain, etc. , boundary-fitted grid is used, the irregular domain in physical plane is transformed into a rectangular domain in transformed plane, and the depth-averaged momentum equations and mass equation are rewritten and discretized based on the finite volume techniques in curvilinear coordinates. Practical application of the method is illustrated by an example for the Dachangzhen Section of the Yangtze River. A fair agreement between the values measured and computed demonstrates the validity of the method developed.     

A NUMERICAL MODEL OF FLOW FIELD AND WATER QUALITY FOR TIDAL REGIONS BASED ON TRIANGULAR MESHES

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＵｐｔｏｎｏｗ ,ｔｈｅｒｅｐｏｒｔｓｆｏｒｓｏｌｖｉｎｇ 2Ｄｄｅｐｔｈ ｉｎｔｅｇｒａｔｅｄｅｑｕａｔｉｏｎｓｏｆｆｌｏｗａｎｄｍａｓｓｔｒａｎｓｐｏｒｔｉｎｔｉｄａｌｒｅｇｉｏｎｈａｖｅｂｅｅｎｉｎｔｒｏｄｕｃｅｄｉｎｌａｒｇｅｎｕｍ ｂｅｒｓ .ＦｒｏｍｔｈｅｂｅｇｉｎｎｉｎｇｏｆＹａｎｅｎｋｏ[1] .ＴｈｅＦｉ ｎｉｔｅＤｉｆｆｅｒｅｎｃｅＭｅｔｈｏｄ (ＦＤＭ )ｈａｓｂｅｅｎｗｉｄｅｌｙａｐｐｌｉｅｄｂｙＦａｌｃｏｎｅｒ[2 ] ,ＶｉｎｃｅｎｚＣａｓｕｌｌｉ[3,5] ,ＨｅＳｈ…     

NUMERICAL SIMULATION AND COMPARISON OF WATER INTAKE-OUTLET METHODS IN POWER PLANTS

The eclipsed form arrangement and march-past method of water intake-outlet arrangements in power plants were researched by 3-D numerical simulation based on the k-ε two-equation turbulence model. Firstly, the flowing characteristics of eclipsed form arrangement were analyzed and the effects of some main factors on inlet temperature were investigated. The simulation results are basically in agreement with those of the previous experiments. Then, by comparing the inlet temperature of the above two intake-outlet methods, the superiority and its existent conditions of the eclipsed form were examined.     

INTERVAL FINITE VOLUME METHOD FOR UNCERTAINTY SIMULATION OF TWO-DIMENSIONAL RIVER WATER QUALITY

Under the interval uncertainties, by incorporating the discretization form of finite volume method and interval algebra theory, an Interval Finite Volume Method (IFVM) was developed to solve water quality simulation issues for two-dimensional river when lacking effective data of flow velocity and flow quantity. The IFVM was practically applied to a segment of the Xiangiiang River because the Project of Hunan Inland Waterway Multipurpose must be started working after the environmental impact assessment for it. The simulation results suggest that there exist rather apparent pollution zones of BODs downstream the Dongqiaogang discharger and that of COD downstream Xiaoxiangjie discharger, but the pollution sources have no impact on the safety of the three water plants located in this river segment. Although the developed IFVM is to be perfected, it is still a powerful tool under interval uncertainties for water environmental impact assessment, risk analysis, and water quality planning, etc. besides water quality simulation studied in this paper.     

NUMERICAL SIMULATION FOR CONTAMINANTS AND WATER TRANSPORT IN SOILS

ＮＵＭＥＲＩＣＡＬ　ＳＩＭＵＬＡＴＩＯＮ　ＦＯＲ　ＣＯＮＴＡＭＩＮＡＮＴＳ　ＡＮＤ　ＷＡＴＥＲ　ＴＲＡＮＳＰＯＲＴ　ＩＮ　ＳＯＩＬＳＭＥＲＩＣＡＬＳＩＭＵＬＡＴＩＯＮＦＯＲＣＯＮＴＡＭＩＮＡＮＴＳＡＮＤＷＡＴＥＲＴＲＡＮＳＰＯＲＴＩＮＳＯＩＬＳ￥Ｗａ...     

THE PREDICTION OF WATER AND SALT REGIME IN SALTAFFECTED AREAS BY NUMERICAL SIMULATION

ＴＨＥＰＲＥＤＩＣＴＩＯＮＯＦＷＡＴＥＲＡＮＤＳＡＬＴＲＥＧＩＭＥＩＮＳＡＬＴＡＦＦＥＣＴＥＤＡＲＥＡＳＢＹＮＵＭＥＲＩＣＡＬＳＩＭＵＬＡＴＩＯＮ￥ＺｈａｎｇＹｕ－ｆａｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＩｒｒｉｇａｔｉｏｎａｎｄＤｒａｉｎａｇｅ，Ｗｕｈａ...     

FINITE ELEMENT NUMERICAL SIMULATION FOR THE HYDRODYNAMIC FIELD EVOLUTION OF GEOTHERMAL WATER IN THE NANWENQUAN ANTICLINE IN CHONGQING IN CHINA

1. INTRODUCTION The Nanwenquan anticline is the drape storing geothermal water. The anticline extends from north to south in Chongqing, the Nanwenquan and Xiaoquan in the middle of the anticline [1]. The two hot springs, and geothermal water in the other …     

WATER BREAKTHROUGH SIMULATION IN NATURALLY FRACTURED GAS RESERVOIRS WITH WATER DRIVE

NOMENCLATURE Δt———ti me increment T———fracture trans missibility Vb———bulk volume S———saturation K———formation permeabilityKr———relative permeability q———production rate Ф———fluid potential φ———porosity u———viscosity P———capillary pressure I———the exchange term L———fracture spacing ω———upstream weighting factor δ———shape factor ξ———inertial factor SUBSCRIPTS mac———macrofracture mic———microfracture m———matrix x———x-dire…     

FUZZY MODEL FOR TWO-DIMENSIONAL RIVER WATER QUALITY SIMULATION UNDER SUDDEN POLLUTANTS DISCHARGED

Based on the fuzziness and impreciseness of water environmental system, the fuzzy arithmetic was used to simulate the fuzzy and imprecise relations in modeling river water quality. By defining the parameters of water quality model as symmetrical triangular fuzzy numbers, a two-dimensional fuzzy water quality model for sudden pollutant discharge is established. From the fuzzy model, the pollutant concentrations, corresponding to the specified confidence level of α, can be obtained by means of the α-cut technique and arithmetic operations of triangular fuzzy numbers. Study results reveal that it is feasible in theory and reliable on calculation applying triangular fuzzy numbers to the simulation of river water quality.     

NUMERICAL SIMULATION OF A MATHEMATICAL MODEL FOR WAVE PROPAGATION ON NON-UNIFORM CURRENT AND DEPTH

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＢｅｒｋｈｏｆｆ( 1 972 )ｄｅｒｉｖｅｄｔｈｅｗｅｌｌ ｋｎｏｗｎｃｏｍ ｂｉｎｅｄｒｅｆｒａｃｔｉｏｎ ｄｉｆｆｒａｃｔｉｏｎｅｑｕａｔｉｏｎｗｈｉｃｈｗａｓａｌｓｏｎａｍｅｄａｓｍｉｌｄ ｓｌｏｐｅｅｑｕａｔｉｏｎ .Ｔｈｅｅｑｕａｔｉｏｎｏｖｅｒ ｃｏｍｅｓｔｈｅｓｈｏｒｔｃｏｍｉｎｇｓｏｆｏｎｌｙｄｉｓｃｕｓｓｉｎｇｒｅｆｒａｃｔｉｏｎｐｈｅｎｏｍｅｎｏｎｆｏｒｔｈｅｒｅｆｒａｃｔｉｏｎｍｏｄｅｌａｎｄｏｎｌｙｓｔｕｄｙ ｉｎｇｄｉｆｆｒａｃｔｉｏｎｐｒｏｂｌｅｍｆｏ…     

THREE-DIMENSIONAL NUMERICAL SIMULATION OF BOD-DO FOR LARGE RESERVOIR

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＢｅｃａｕｓｅｔｈｅｒｅａｒｅｍａｎｙｂｕｉｌｔａｎｄｂｕｉｌｄｉｎｇｌａｒｇｅｄｅｅｐｒｅｓｅｒｖｏｉｒｓｉｎＣｈｉｎａ ,ｔｈｅｓｔｕｄｙｏｆｔｈｅｍｏｄｅｌｏｆＢｉ ｏｌｏｇｉｃａｌＯｘｙｇｅｎＤｅｍａｎｄ (ＢＯＤ)ａｎｄＤ     

APPLICATION OF LARGE SCALE TURBULENT SIMULATION FOR WATER QUALITY MODELLING OF THE YANGTZE RIVER

Large scale turbulent structures play an important role in mass transport of natu-ral river turbulence diffusion,After adopting the theory of Large Scale Turbulent Simulation tonatural rivers,some 1-D stream quality models,such as QUAL-Ⅱ,have been widely applied tolarge,middle and small rivers in China with reasonable success.Moreover,on this basis,2-Dand 3-D river quality models have also been developed.Both 2-D and 3-D models used upwindscheme plus Peaceman-Rachford's alternating scheme in the first one and Douglas'scheme inthe second one.These models have also been successfully applied to the Yangtze River as well assome middle and small rivers in China.     

MATHEMATICAL MODEL FOR 2-D TIDAL FLOW AND WATER QUALITY WITH ORTHOGONAL CURVILINEAR COORDINATES

1 .　INTRODUCTIONThedischargeofpollutedwaterisbecominganincreasingthreattotheresourcesintidalareas.Thenumericalsimulatingthe 2 Dtidalflowandwaterqualityisthebasisofwaterresource plan ningandmanagement.Inrecentyears,althoughconsiderableattentionhasbeenfocusedonthisproblem ,thecomputationaldifficultiesinnaturaltidalriversremaintobeabigproblem ,suchasthecomplicatedboundaryconfigurations ,the greatdisparitybetweenlengthandwidth ,etc .Inthefollowing ,a 2 Dnumericalmodelbasedonthealternating…     

3D NUMERICAL SIMULATION ON WATER AND AIR TWO-PHASE FLOWS OF THE STEPS AND FLARING GATE PIER

1. INTRODUCTION Withtheincreasingofthenumberofthehigh damandtheunitdischargethroughthespillway, theexpertsandscholarshavepaidmoreattention tothemethodofenergydissipation.Asetofphys icalexperimentalresearchonsteppedspillwayhas beencarriedout[1,2].Innumericalsimulation,Un amietal.[3]gavethetwo dimensionnumerical modelofspillwayflow,andSongetal.[4]calculat edthefreesurfaceflowoverspillway.Liuetal.[5] simulatedthewaterflowoveraweirwith2Dk ε turbulentmodel.Xuetal.[6]calculatedthe3Dcompl…     

NUMERICAL SIMULATION OF 2D HORIZONTAL COOLING WATER DISCHARGE IN GENERALIZED CURVILINEAR COORDINATE

1. INTRODUCTIONResearch on the movement characteristics ofcooling water is a hot spot presently , which hasgreat significance to maintain the balance of eco-logical system. Mathematical models and physicalmodels are major means for this study .In recentyears , Chen[1 ,2]has presentsed a 2D horizontalmathematical model based on the hybrid methodand finite element mesh, Zhang[3]has provided afinite layer model for 2D thermal density flowinopen channel . Wu[4]has developped an unsteady2D h…     

DEVELOPMENT OF TWO-DIMENSIONAL HYDRODYNAMIC AND WATER QUALITY MODEL FOR HUANGPU RIVER

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＨｕａｎｇｐｕＲｉｖｅｒ,ｏｒｉｇｉｎａｔｉｎｇｆｒｏｍｔｈｅＴａｉｈｕ ,ｒｕｎｓａｃｒｏｓｓＳｈａｎｇｈａｉａｎｄｆｅｅｄｓｉｎｔｏＹａｎｇｔｚｅＲｉｖｅｒａｔＷｕｓｏｎｇｋｏｕ .Ｉｔｉｓａｔｉｄａｌｉｎｆｌｕｅｎｃｉｎｇｒｉｖｅｒｗｉｔｈｍｏｒｅｔｈａｎ 5 0ｔｒｉｂｕｔａｒｉｅｓａｍｏｎｇｗｈｉｃｈｓｏｍｅｍａｊｏｒｔｒｉｂｕ ｔａｒｉｅｓａｒｅｓｈｏｗｎｉｎＦｉｇ .1 .Ｆｉｇ .1　ＤｅｐｉｃｔｉｏｎｏｆＨｕａｎｇｐｕＲｉｖｅｒｗａｔｅｒｓｈｅｄＮｏｗａｄａｙｓｔｈ…     

A COUPLED MODEL OF HYDRODYNAMICS AND WATER QUALITY FOR YUQIAO RESERVOIR IN HAIHE RIVER BASIN

In order to simulate the characteristics of hydrodynamic field and mass transport processes in the Yuqiao Reservoir （YQR）, a 2-D coupled model of hydrodynamics and water quality was developed, and the water-quality related state variables in this model included CODMn, TN and TP. The hydrodynamic model was driven by employing observed winds and daily measured flow data to simulate the seasonal water cycle of the reservoir. The simulation of the mass transport and transformation processes of CODMn, TN and TP was based on the unsteady diffusion equations, driven by observed meteorological forcing and external loadings, with the fluxes form the bottom of reservoir and the plant photosynthesis and respiration as internal sources and sinks. A finite volume method and Alternating Direction Implicit （ADI） scheme were used to solve these equations. The model was calibrated and verified by using the data observed from YQR in two different years. The results showed that in YQR, the wind-driven current was an important style of lake current, while the concentration of water quality item was decreasing from east to west because of the external pollutant loadings. There was a good agreement between the simulated and measured values, with the minimal calculation error percent of 0.1% and 2.6% and the mean error percent of 44.0% and 51.2% for TN and TP separately. The simulation also showed that, in YQR, the convection was the main process in estuaries of inflow river, and diffusion and biochemical processes dominate in center of reservoir. So it was necessary to build a pre-pond to reduce the external loadings into the reservoir.     

NUMERICAL SIMULATION AND FIELD IMPLEMENTATION OF SURFACTANT FLOODING

1. INTRODUCTIONThe main problems inthe development processof low permeability oilfield are that high pressureof water-injection, low efficiency of water dis-placement and the ulti mate recovery efficiency ofwater flooding is just about 30 percent[1]. Expe…     

NUMERICAL SIMULATION OF ARTIFICIAL VENTILATED CAVITY

1. INTRODUCTION The cavitation phenomenon[1,2] has already been paid high attention as a primary characteristic in the process of underwater body’s manufacture and exploitation. For a long time, the purpose of cavitation research is to prevent the occurr…     

NUMERICAL SIMULATION OF BUBBLE FLOW INTERACTIONS

Bubble flow interaction can be important in many practical engineering applications. For instance, cavitation is a problem of interaction between nuclei and local pressure field variations including turbulent oscillations and large scale pressure variations. Various types of behaviours fundamentally depend on the relative sizes of the nuclei and the length scales of the pressure variations as well as the relative importance of bubble natural periods of oscillation and the characteristic time of the field pressure variations. Similarly, bubbles can significantly affect the performance of lifting devices or propulsors. We present here some fundamental numerical studies of bubble dynamics and deformation, then a practical method using a multi-bubble Surface Averaged Pressure (DF-Multi-SAP©) to simulate cavitation inception and scaling, and connect this with more precise 3-D simulations. This same method is then extended to the study of two-way coupling between a viscous compressible flow and a bubble population in the flow field.