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1.  A type of dynamic mechanism of river hydraulic geometry  
   BAI YuChuan  JI ZiQing  ZHANG MingJin《中国科学:技术科学(英文版)》,2014年第57卷第4期
   Large-scale structure of river flow is the main driving force for bed erosion-deposition and bank deformation.The structure shapes and retains a corresponding hydraulic geometry form.Therefore,the most stable flow structure is the probable natural river plane formation.Natural coordinate transformation and perturbation methods were adapted to deform the governing equations of sine-generated river basic flow and disturbance flow independently.The stability and retention of perturbation waves were analyzed in our model to explain why meandering rivers followed a certain type of flow path.Computation results showed that all types of perturbation waves in meandering rivers were most stable when the meandering wave number was about 0.39–0.41.We believe that this type of stable flow structure shaped a certain meandering river.The statistical average length-width ratios of Yalin,Habib and da Silva and Leopold and Wolman somewhat confirmed our most stable river meandering wave number.In some ways,meandering rivers always tend to diminish internal turbulence intensity.    

2.  Fluvial processes and their impact on the finless porpoise’s habitat after the Three Gorges Project became operational  
   FANG HongWei  HE GuoJian  HAN Dong  DUAN JieHui  HUANG Lei  CHEN MingHong《中国科学:技术科学(英文版)》,2014年第57卷第5期
   Since the filling of the reservoir of the Three Gorges Project(TGP)dam in the Yangtze River in 2003,erosion downstream from the dam site has affected the finless porpoise’s habitat.In this study,a one-dimensional(1D)fluvial process mathematical model is used to calculate flow and sediment transport in the middle and lower reaches of the Yangtze River,including the finless porpoise’s habitat.By analyzing the calculation results for the water resources,suspended load,and bed materials in the finless porpoise’s habitat after the riverbed deformation,we evaluated the possible impact on this rare Yangtze River aquatic animal.The results show that,with the erosion of riverbed over the next 20 years,the water quantity comprising the habitat will decrease to half of its present amount,and the bed materials will be eroded to coarse grading,such that the reserve will become a gradually disappearing stream.Effective engineering measures should be used to decrease the erosion in the main channel,in case the overall erosion cannot be stemmed and controlled,to ensure an adequate water volume flows into the finless porpoise’s habitat.    

3.  QUANTITATIVE APPROACH TO INFLUENCES OF HIGH SEDIMENT LADEN INUNDATION FLOWS ON THE MORPHOLOGICAL VARIATION OF FLOODPLAINS  被引次数:3
   ZHANG Xin-hua LONG Wen-fei LEI Xiao-zhang ZHANG Xiang-wei XIE He-ping WANG Jiang-ping《水动力学研究与进展(英文版)》,2007年第19卷第1期
   This article mainly aims at developing an integrated 2-D numerical simulation model on inundation, sediment transportation and the morphological variations of floodplains due to high sediment-laden inundation flows. Due to the complexity of inner and outer boundaries and the arbitrary structures within the computational domain of floodplains, an unstructured Finite-Volume Method (FVM) based on an irregular polygon mesh was worked out so that the influences of complex boundaries can be integrated into the simulation. A case study was conducted in the Lower Yellow River Basin, in which a dike-break at the Huayuankou Hydrological Station was assumed to happen when a flood scale of 1982 was suffered in the region. The simulated spatial distribution of sediment deposition and erosion can be used to reasonably explain the natural phenomena of “suspended river” of the lower part of the Yellow River. It is concluded that the inundation process of water is similar to a variable-river-bed condition during the simulation because the sediment deposition and erosion are modified by new values at the end of each time step. The mass and momentum conservation were strictly followed during the simulation. Therefore, theprediction of floodplain evolutions by the integrated simulation model, proposed in this study, can be adequately and accurately given if the real condition of an floodplain can be obtained in detail.    

4.  STUDY OF THE FLOW THROUGH NON-SUBMERGED VEGETATION  被引次数:5
   NEHAL Laounia YAN Zhong-min XIA Ji-hong《水动力学研究与进展(英文版)》,2005年第17卷第4期
   Vegetation is an important feature of many rivers. Vegetation along rivers produces high resistance to flow and, as a result, has a large impact on water levels in rivers and lakes. The effects of instream-unsubmerged vegetation (such as the reed-similar Kalmus) on flow resistance and velocity distributions is studied in the paper. Artificial vegetation is used in the experimental study to simulate the Acorus Calmus L. As shown in experimental tests the resistance depends strongly on vegetation density and the Manning resistance coefficient varies with the depth of flow. A simplified model based on concepts of drag is developed to evaluate the roughness coefficient (Manning's n) for non submerged vegetation. In vegetated channels the overall flow resistance is influenced significantly by the distribution pattern of the vegetated beds. Within vegetation, vertical variation in velocity is different from that in the non vegetated bed, which reflects the variation in vegetation density. Vertical turbulent transport of momentum is negligible as demonstrated by experiments.    

5.  SIMULATION OF SEDIMENT-LADEN FLOW BY DEPTH-AVERAGED MODEL BASED ON UNSTRUCTURED COLLOCATED GRID  被引次数:5
   LIU Shi-he LUO Qiu-shi MEI Jun-ya《水动力学研究与进展(英文版)》,2007年第19卷第4期
   The 2-D depth-averaged mathematical model for sediment-laden flows has been widely used in river control and other related engineering problems, and now it is usually solved on structured grids. Since the natural river is usually very complicated in plane boundary, and unstructured grids are more attractive in solving the problems with complicated domains, the following questions about solving 2-D depth-averaged model were discussed in this article: (1) a modified Bowyer algorithm was suggested to generate unstructured grids for natural rivers, (2) the Finite Volume Method (FVM) is employed to discretize the governing equations of the 2-D depth-averaged model and an implicit scheme was suggested with unstructured collocated grids, (3) the observed hydrological data of the Chenglingji Reach in the Yangtze River are used for verification of the presented method. It seems that the suggested numerical scheme works very well, and the simulation results of both hydraulic characteristics and river bed deformation are in good agreement with the observed ones.    

6.  A RIVER FLOW ROUTING MODEL BASED ON DIGITAL DRAINAGE NETWORK  
   YUAN Fei REN Li-liang YU Zhong-bo XU Jing《水动力学研究与进展(英文版)》,2005年第17卷第4期
   On the basis of Digital Elevation Model (DEM) data, watershed delineation and spatial topological relationship were proposed by the Digital Elevation Drainage Network Model (DEDNM) for the area upstream of the Hanzhong Hydrological Station in the Hanjiang River in China. Then, the Muskingum-Cunge method considering lateral flow into the river was applied to flood routing on the platform of digital basin derived from DEDNM. Because of considering lateral flow into the river, the Muskingum-Cunge method performs better than the Muskingum method in terms of the Nash-Sutcliffe model efficiency coefficient and the relative error of flood discharge peak value. With a routing-after-superposition algorithm, the Muskingum-Cunge method performs better than the Muskingum method in terms of the Nash-Sutcliffe model efficiency coefficient and the relative error of flood discharge peak value. As a result, the digital basin coupled with the Muskingum-Cunge method provides a better platform for water resources management and flood control.    

7.  A NEW MEASURE FOR DIRECT MEASUREMENT OF THE BED SHEAR STRESS OF WAVE BOUNDARY LAYER IN WAVE FLUME  
   HUO Guang WANG Yi-gang YIN Bao-shu YOU Zai-jin《水动力学研究与进展(英文版)》,2007年第19卷第4期
   In this article, a shear plate was mounted on the bottom in a wave flume and direct measurements of the smooth and rough bed shear stress under regular and irregular waves were conducted with the horizontal force exerted on the shear plates by the bottom shear stress in the wave boundary layer. Under immobile bed condition, grains of sand were glued uniformly and tightly onto the shear plate, being prevented from motion with the fluid flow and generation of sand ripples. The distribution of the bottom mean shear stress varying with time was measured by examining the interaction between the shear plate and shear transducers. The relation between the force measured by the shear transducers and its voltage is a linear one. Simultaneous measurements of the bottom velocity were carried out by an Acoustic Doppler Velocimeter (ADV), while the whole process was completely controlled by computers, bottom shear stress and velocity were synchronously measured. Based on the experimental results, it can be concluded that (1) the friction coefficient groews considerably with the increase of the Reynolds number, (2) the shear stress is a function varying with time and linearly proportional to the velocity. Compared with theoretical results and previous experimental data, it is shown that the experimental method is feasible and effective, A further study on the bed shear stress under regular or irregular waves can be carried out. And applicability to the laboratory studies on the initiation of sediments and the measurement of the shear stress after sediment imigration.    

8.  RESISTANCE OF FLOW OVER ROUGH BED  
   《水动力学研究与进展(英文版)》,1991年第4期
   In this paper,the flow resistance in a flume with rough bed was studied,and the criteria of 2-dimensionalflow were obtained.The effects of bed roughness on Manning coefficient n and Chézy coefficient C were also dis-cussed,and the experimental results indicate that n and C can be taken as constants for small-scale roughness case.    

9.  THREE-DIMENSIONAL NUMERICAL MODEL FOR WINDING TIDAL RIVER WITH BRANCHES  被引次数:3
   YANG Li-ling WANG Yun-hong ZHU Zhi-xia XU veng-jun DENG Jia-quan YANG Fang《水动力学研究与进展(英文版)》,2007年第19卷第2期
   Natural rivers are usually winding with branches and shoals,which are difficult to be simulated with rectangular grids. A 3-D current numerical model was established based on the orthogonal curvilinear coordinate system and vertical σ coordinate system. The equations were discretisized using a semi-implicit scheme. The “predictor” and “corrector” steps were applied for the horizontal momentum equations to meet the basic requirement that the depth-integrated currents obtained from the equations for 2-D and 3-D modes have identical values. And a modification of traditional method of dry/wet discriminance was proposed to determine accurately the boundary and ensure the continuity of variable boundary in the simulation. This model was verified with the data measured in a winding tidal river with branches in April,2004. The simulated data of water levels and velocities agree well with the measured ones,and the computed results reveal well the practical flow characteristics,including the vertical secondary flow in a winding reach.    

10.  Water level updating model for flow calculation of river networks  
   Xiao-ling WU Xiao-hua XIANG Li LI Chuan-hai WANG《水科学与水工程》,2014年第1期
   Complex water movement and insufficient observation stations are the unfavorable factors in improving the accuracy of flow calculation of river networks. A water level updating model for river networks was set up based on a three-step method at key nodes, and model correction values were collected from gauge stations. To improve the accuracy of water level and discharge forecasts for the entire network, the discrete coefficients of the Saint-Venant equations for river sections were regarded as the media carrying the correction values from observation locations to other cross-sections of the river network system. To examine the applicability, the updating model was applied to flow calculation of an ideal river network and the Chengtong section of the Yangtze River. Comparison of the forecast results with the observed data demonstrates that this updating model can improve the forecast accuracy in both ideal and real river networks.    

11.  COMPUTATIONAL RESEARCH ON WAVE MAKING OF MOVING WIGLEY HULL IN TIME DOMAIN  
   YANG Xiang-hui  YE Heng-kui  FENG Da-kui  LIU Juan《水动力学研究与进展(B辑)》,2008年第20卷第4期
   Based on Green's theorem, a time domain numerical model was constructed to simulate wave making phenomenon caused by a moving ship. In this article, the Rankine sources and dipoles were placed on boundary surfaces (i.e., the ship surface and free surface), and a time-stepping scheme was employed. Its unique characteristic is that steady state can be realized from initial value by employing the time-stepping scheme and unsteady free surface conditions. In time domain, if the results of unsteady flow problem tend to data stabilization after many time steps of computation, they could be regarded as the data of steady ones. This model could be employed to steady or unsteady problems. Theoretical reasoning and computational process of this method was described in detail The linear and nonlinear boundary conditions on body surface were studied, and the relative means to realize these boundary conditions in iterative computation were also discussed. Some proper parameters about the model of the Wigley hull were determined by many numerical tests, and their influences on wave making resistance and wave pattern were discussed. According to the comparison between numerical results and data available in relative references, the method used in this work is proven to be a reliable method in time domain. And the lattice reorganization in every time step computation is a feasible numerical approach.    

12.  Stream Surface Strip Element Method and Simulation of Three-Dimensional Deformation of Continuous Hot Rolled Strip  被引次数:5
   LIUHong-min WANGYing-rui《钢铁研究学报(英文版)》,2004年第11卷第2期
   A new method, the stream surface strip element method, for simulating the three-dimensional deformation of plate and strip rolling process was proposed. The rolling deformation zone was divided into a number of stream surface (curved surface) strip elements along metal flow traces, and the stream surface strip elements were mapped into the corresponding plane strip elements for analysis and computation. The longitudinal distributions of the lateral displacement and the altitudinal displacement of metal were respectively constructed to be a quartic curve and a quadratic curve, of which the lateral distributions were expressed as the third-power spline function, and the altitudinal distributions were fitted in the quadratic curve. From the flow theory of plastic mechanics, the mathematical models of the three-dimensional deformations and stresses of the deformation zone were constructed. Compared with the streamline strip element method proposed hy the first author of this paper, the stream surface strip element method takes into account the uneven distributions of stresses and deformations along altitudinal direction, and realizes the precise three-dimensional analysis and computation. The simulation example of continuous hot rolled strip indicates that the method and the model accord with facts and provide a new reliable engineering-computation method for the three-dimensional mechanics simulation of plate and strip rolling process.    

13.  VELOCITY DISTRIBUTION IN TRAPEZOID-SECTION OPEN CHANNEL FLOW WITH A NEW REYNOLDS-STRESS EXPRESSION  被引次数:1
   Ma ZhengShanghai Institute of Applied Mathematics and Mechanics  Shanghai University  Shanghai 200072  China  e-mail:mazh8888@sina. com《水动力学研究与进展(英文版)》,2003年第15卷第6期
   By considering that the coherent structure is the main cause of the Reynolds stress, a new Reynolds stress expression was given. On this basis the velocity distribution in the trapezoid-section open channel flow was worked out with the pseudo-spectral method. The results were compared with experimental data and the influence of the ratio of length to width of the cross-section and the lateral inclination on the velocity distribution was analyzed. This model can be used the large flux in rivers and open channes.    

14.  Numerical investigation of swash zone hydrodynamics  
   JIANG ChangBo  DENG Bin  HU ShiXiong  TANG HanSong《中国科学:技术科学(英文版)》,2013年第56卷第12期
   This paper presents a novel numerical model using a fully three-dimensional(3D),incompressible,two-phase flow NavierStokes(NS)solver,which are discretized by the finite volume method.A high-resolution STACS-VOF method is used to capture the interface between the air and water phases.The validity of the simulation following this model is examined through3D shear flow and collapsing cylinder of water.Then,this proposed model is adopted to simulate the dynamics of flow involved with surge bore propagating over a slope in the swash zone.The computed uprush shoreline motion and the tip of runup water surface agreed well with experimental data,which indicates that this model can describe the aerated flow accurately.Numerical analyses are also applied to the spatial and temporal distributions of free-surface,instantaneous flow field,and maximal bed shear stress in the bore collapse,uprush and backwash processes.The results from the analyses reveal that the flow dynamics is complicated after the bore breaks,and the proposed model can well capture the structure characteristics of sheet flow,which are better than the previous results.All these findings are of help to understand the pattern of sediment transport and coastal evolution in the swash zone.    

15.  萃取体系滴内和两相阻力控制的单液滴传质实验和数值模拟研究  
   李天文  毛在砂  陈家镛  费维扬《中国化学工程学报》,2002年第10卷第1期
   Numerical simulation of transient mass transfer to a single drop controlled by the internal resistance or by the resistance in both phases was mathematically formulated and simulated in a boundary-fitted orthogonal coordinate system. The simulated results on the transient mass transfer dominated by the internal resistance are in good agreement with the Newman and Kronig-Brink models for drops with low Reynolds number. When the drop Reynolds number is up to 200, the mass transfer coefficient from numerical simulation is very low as compared with the Handlos-Baron model. The cases with mass transfer resistance residing in both the continuous and drop phases were simulated successfully and compared with the experimental data in three extraction systems recommended by European Confederation of Chemical Engineering (EFCE). For single drops with Re < 200, the numerically predicted values of the extraction fraction and overall mass transfer coefficient are in reasonable coincidence with the experimental data. It is concluded that the numerical simulation can be resorted in some cases of solvent extraction for conducting numerical experiments and parametric study. Nevertheless, for better resolution as higher Reynolds number drops are simulated, more sophisticated techniques should be developed and incorporated to deal with the large deformation and transient shape oscillation as well as possible Marangoni effect.    

16.  Risk analysis of slope instability of levees under river sand mining conditions  
   《水科学与水工程》,2012年第3期
   Levees are affected by over-exploitation of river sand and river adjustments after the formation of sand pits. The slope stability is seriously threatened, drawing wide concern among experts and scholars in the area of water conservancy. This study analyzed the uncertainties of slope stability of levees under river sand mining conditions, including uncertainty caused by interest- driven over-exploitation by sand mining contractors, and uncertainty of the distance from the slope or sand pit to the bottom of the levee under the action of cross-flow force after the sand pit forms. Based on the results of uncertainty analysis, the distribution and related parameters of these uncertainties were estimated according to the Yangtze River sand mining practice. A risk model of the slope instability of a levee under river sand mining conditions was built, and the possibility of slope instability under different slope gradients in a certain reach of the Yangtze River was calculated with the Monte Carlo method and probability combination method. The results indicated that the probability of instability risk rose from 2.38% to 4.74% as the pits came into being.    

17.  Determination of pile failure mechanism under pullout test in loose sand  
   K.Faizi  R.Kalatehjari  R.Nazir  A.S.A.Rashid《中南工业大学学报(英文版)》,2015年第4期
   Estimating the deformation of soil around the pile contributes to reliable design of structures under pullout force. This work presents the results of a series of small-scale physical modelling tests designed to investigate the uplift resistance of piles with diameter of 5 cm and slenderness ratios of 1, 2, 3 and 4 in loose sand. Close photogrammetric technique and particle image velocimetry(PIV) were employed to observe the failure patterns due to uplift force on piles. The results show that the shear zones curve slightly outward near the ground surface. After peak resistance, the shear strain concentrates into a pair of narrow shear bands,then a flow around mechanism is formed accompanied by a reduction in the uplift resistance. The results from the laboratory tests were verified by analytical method proposed by Chattopadhyay and PLAXIS 2D and 3D finite element method software. It is found that the depth and width of the failure surface increase with the increment of the slenderness ratio. A good agreement is observed among the measured bearing capacity and obtained failure surface of the models and the results of numerical modelling. Finally, the maximum deformation of loose and dense sand respectively with densities of 25% and 75% were compared in the stage of fully removing pile. The results shows that the deformation of the soil is related to its density, therefore it depends on its dilatancy.    

18.  A Preliminary Study on 1D Numerical Experiment of Water Debris Flow in Gully  
   LIU Tonghuan~1 WANG Xiekang~1 CUI Peng~2 《四川大学学报(工程科学版)》,2005年第Z1期
   In order to improve and enhance the numerical modeling methods and its application on debris flow problems,a preliminary study has been proposed in accordance with the corrected water-sediment numerical model on the premise of revised resistance and sediment capacity equations.Firstly,an overview the recent re- search achievements on numerical simulation of debris flow has been conducted,the results shown that a gener- al numerical model for debris flow can not be existed at all because the complex rheological behavior and main evolution processes from initiation,movement to deposition with different physical mechanism.Secondly,as- suming the one-dimensional Saint-Venant equation for the approximation of water debris flow movement in the gully based on the Manning's equation for the friction slope of water debris flow,the conservation equations of mass and momentum have been solved by means of centre-difference in distance longitudinal axis of the gully and weighted coefficient in time field,the distribution of depth,velocity and scoured or deposition in each sec- tion have been obtained using a suitable sediment transport rate.The aim in this work is focus on improvement of water-sediment model to adapt debris flow numerical simulation although this result need further to analyze and discuss as far as the reliability and precision were concerned because this model proposed must have e- nough the field observational or experimental data to verify related model parameter.    

19.  1,2-环已二醇在溶液中的溶解度  
   周彩荣  王海峰  蒋登高《中国化学工程学报》,2005年第13卷第4期
   The solubility of trans-1,2-cyclohexanediol in water, methyl acetate, acetic ester, propyl acetate, butyl acetate, methyl acrylate, ethyl acrylate, 2-pentanone and acetoacetic ester was measured at temperatures ranging from about 300K to 330K, using a modification of the experimental technique of laser monitoring observation system. The solubilities were calculated by λh method, in which new parameters were introduced to express the activity coefficients of trans-1,2-cyclohexanediol, and determined from the experimental data. The new parameters provide good calculated results. The experimental data were also correlated with a simple model, and results were compared with present λh model.    

20.  MODELING DAM-BREAK FLOOD OVER NATURAL RIVERS USING DISCONTINUOUS GALERKIN METHOD  
   KHAN Abdul A.《水动力学研究与进展(B辑)》,2012年第4期
   A well-balanced numerical model is presented for two-dimensional, depth-averaged, shallow water flows based on the Discontinuous Galerkin (DG) method. The model is applied to simulate dam-break flood in natural rivers with wet/dry bed and complex topography. To eliminate numerical imbalance, the pressure force and bed slope terms are combined in the shallow water flow equations. For partially wet/dry elements, a treatment of the source term that preserves the well-balanced property is presented. A treatment for modeling flow over initially dry bed is presented. Numerical results show that the time step used is related to the dry bed criterion. The intercell numerical flux in the DG method is computed by the Harten-Lax-van Contact (HLLC) approximate Riemann solver. A two-dimensional slope limiting procedure is employed to prevent spurious oscillation. The robustness and accuracy of the model are demonstrated through several test cases, including dam-break flow in a channel with three bumps, laboratory dam-break tests over a triangular bump and an L-shape bend, dam-break flood in the Paute River, and the Malpasset dam-break case. Numerical results show that the model is robust and accurate to simulate dam-break flood over natural rivers with complex geometry and wet/dry beds.    

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