MULTI-OBJECTIVE OPTIMIZATION DESIGN FOR TRANSONIC TURBINE CASCADES USING SIMULATED ANNEALING ALGORITHM

1.mTRonUCmNKirkpatricketal(1982)Pointedoutthatthereexistsananalogybetweencombinatorialoptimizationproblemandsolidannealingprocess-Inthelightofthisanalogy,Metropolisetalmedelledtheprocessthatsolidapprochesthermalequilibrium,andworkedouttheMetroPoliscriterionintheoptimizationprocess.Subsequently,theydevelopedakindofiter-ativeandcombinatorialoptimizationalgorithm,whichiscalledthesimulatedannealingalgo-rithm(SAA).SAAisasearchalgorithmbasedontheMonte-Carlomethedusedinstatisticalmechan-icsofan…     

A RIVER FLOW ROUTING MODEL BASED ON DIGITAL DRAINAGE NETWORK

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.     

Development of Optimization Schemes for Floodplain Management; A Case Study

In this paper, two optimization models are presented. The first model is developed to determine economical combination of permanent and emergency flood control options and the second one is used to determine the optimal crop pattern along a river based on the assigned flood control options by the first optimization model. The optimal combination of flood protection options is determined to minimize flood damages and construction cost of flood control options along the river using the genetic algorithm (GA) optimization model. In order to consider the effects of flood control options on hydraulic characteristics of flow, two hydrological routing models for the reservoir and the river are coupled with the optimization model. Discharge–elevation and elevation–damage curves obtained based on separate hydraulic simulations of the river are used for flood damage calculations in the optimization model. The parameters of a hydrologic river routing model are also calibrated using the developed hydraulic model results. The proposed model is applied to the Kajoo river in the south-eastern part of Iran. The results demonstrate an economical integration of permanent and emergency flood control options along the river which include minimum expected value of damages related to floods with different return periods and construction cost of flood control options. Finally the resulting protection scheme is used for land use planning through identifying the optimal crop mix along the river. In this approach, the objective function of the optimization model is an economic function with a probabilistic framework to maximize the net benefit of agricultural activities. The study exhibits the importance of floodplain management and land use planning to achieve the development goals in the river basins.     

基于MATLAB环境的抗滑桩智能优化设计系统

介绍了基于MATLAB的抗滑桩智能优化设计系统的基 本思路,并给出了该系统的总体结构、主要功能以及主要模块--抗滑桩BP网络结合模拟退火遗传算法SAGA(Simulated Annealing Genetic Algorithm)优化设计模块。该系统主要实 现了非线性优化方法和BP网络结合模拟退火遗传算法两种优化方法智能优化抗滑桩设计,最后将该系统应用于云南省祥临公路古滑坡防治方案优化设计。     

A LATTICE BOLTZMANN SUBGRID MODEL FOR LID-DRIVEN CAVITY FLOW

In recent years, the Lattice Boltzmann Method (LBM) has developed into an alternative and promising numerical scheme for simulating fluid flows and modeling physics in fluids. In order to propose LBM for high Reynolds number fluid flow applications, a subgrid turbulence model for LBM was introduced based on standard Smagorinsky subgrid model and Lattice Bhatnagar-Gross-Krook (LBGK) model. The subgrid LBGK model was subsequently used to simulate the twodimensional driven cavity flow at high Reynolds numbers. The simulation results including distribution of stream lines, dimensionless velocities distribution, values of stream function, as well as location of vertex center, were compared with benchmark solutions, with satisfactory agreements.     

A NEW WAKE OSCILLATOR MODEL FOR PREDICTING VORTEX INDUCED VIBRATION OF A CIRCULAR CYLINDER

This article proposes a new wake oscillator model for vortex induced vibrations of an elastically supported rigid circular cylinder in a uniform current. The near wake dynamics related with the fluctuating nature of vortex shedding is modeled based on the classical van der Pol equation, combined with the equation for the oscillatory motion of the body. An appropriate approach is developed to estimate the empirical parameters in the wake oscillator model. The present predicted results are compared to the experimental data and previous wake oscillator model results. Good agreement with experimental results is found.     

IMPROVEMENT OF BUBBLE MODEL FOR CAVITATING FLOW SIMULATIONS

In the present research,a bubble dynamics based model for cavitating flow simulations is extended to higher void fraction region for wider range of applications.The present bubble model is based on the so-called Rayleigh-Plesset equation that calculates a temporal bubble radius with the surrounding liquid pressure and is considered to be valid in an area below a certain void fraction.The solution algorithm is modified so that the Rayleigh-Plesset equation is no more solved once the bubble radius(or void fraction)reaches at a certain value till the liquid pressure recovers above the vapor pressure in order to overcome this problem.This procedure is expected to stabilize the numerical calculation.The results of simple two-dimensional flow field are presented compared with the existing bubble model.     

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.     

A NEW WELL TEST MODEL FOR STRESS-SENSITIVE AND RADIALLY HETEROGENEOUS DUAL-POROSITY RESERVOIRS WITH NON-UNIFORM THICKNESSES

This article presents a new well test model for stress-sensitive composite dual-porosity reservoirs based on the concept of permeability modulus, where the rock and fluid properties as well as the formation thickness vary in the radial direction. An analytical solution in the Laplace space for the pressure-transient behavior for a line-source, constant-rate well of this type of reservoir is obtained with the Laplace transformation and the perturbation technique. The pressure and its derivative in the reserv...     

A STREAMLINE-BASED PREDICTIVE MODEL FOR ENHANCED-OIL-RECOVERY POTENTIALITY

A pseudo-three-dimensional model of potentiality prediction is proposed for enhanced oil recovery, based on the streamline method described in this article. The potential distribution of the flow through a porous medium under a complicated boundary condition is solved with the boundary element method. Furthermore, the method for tracing streamlines between injection wells and producing wells is presented. Based on the results, a numerical solution can be obtained by solving the seepage problem of the stream-tube with consideration of different methods of Enhanced Oil Recovery（EOR）. The advantage of the method given in this article is that it can obtain dynamic calculation with different well patterns of any shape by easily considering different physicochemical phenomena having less calculation time and good stability. Based on the uniform theory basis-streamline method, different models, including CO2 miscible flooding, polymer flooding, alkaline/surfactant/polymer flooding and microbial flooding, are established in this article.     

2-D FLOW AND SEDIMENT SIMULATION FOR THE FLOOD REGULATION OF A RESERVOIR WITH WATER INTAKE

In this paper, the flood regulation by operating the downstream sluice gates for a reservoir with a water intake is studied. The two-dimensional depth-averaged flow equations are solved by the boundary fitted finite volume method (FVM) based on MacCormsck prediction-correction scheme. The bed deformation caused by both the bed load and incoming suspended sediment is determined in a coupled way. The model is used to simulate the practical flood regulation operation of a reservoir. The results have been compared with the physical experiment.     

A LARGE EDDY SIMULATION TURBULENCE MODEL FOR COASTAL SEAS AND SHALLOW WATER PROBLEMS

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A 2-D HYDRODYNAMIC MODEL FOR THE RIVER, LAKE AND NETWORK SYSTEM IN THE JINGJIANG REACH ON THE UNSTRUCTURED QUADRANGLES

The main river,the Dongting Lake and river networks in the Jingjiang reach of the Yangtze River constitute a complex water system,for which a full 2-D hydrodynamic model is established instead of the traditional 1-D or compound models for simulation of such complex systems,based on the latest developments of computer technologies and numerical methods.To better handle irregular boundaries and keep the computation cost well in a reasonable limit,unstructured grids of moderate scale are used. In addition,a dynamic boundary tracking method is proposed to simulate variable flow domains at different floods,especially,when the moderate scale gird can not describe flows in narrow river-network channels at low water levels.Theθsemi-implicit method and the Eulerian-Lagrangian Method(ELM)are adopted,which make the model unconditionally stable with respect to the gravity wave speed and Courant number restrictions.Properties and efficiency of the model are discussed,and it is concluded that the new model is robust and efficient enough for the simulation of a big,complex water system.Validation tests show that the simulation results agree well with field data.It takes about 0.96 h to complete the computation of a 76 d flood,which indicates that the model is efficient enough for engineering applications.     

SIMULATION OF SOLUTE TRANSPORT USING A COUPLING MODEL BASED ON FINITE VOLUME METHOD IN FRACTURED ROCKS

The discrete version of solute transport equation for porous matrix depicted with the continuum model and the discrete fractured-network model are derived for fractured rocks with the Finite Volume Method(FVM).The two models are coupled according to the continuity condition of hydraulic head and concentration and the conservation of flow flux and mass flux in the contact plane between porous matrix and fractures.Numerical results show that the simulated concentration of the coupling model based on the FVM a...     

Combining Population Growth Model and Generalized Additive Model to Determine Optimal Water Level FOR Waterbird Conservation: A Case Study of Siberian Crane (Leucogeranus Leucogeranus) in Lake Poyang,China

Siberian crane (Leucogeranus leucogeranus) is one of the most endangered species in the world. The ecological integrity of its main wintering ground at Poyang Lake in China is crucial for the future of the species because Poyang Lake accommodates 99% of its global population. With the Three Gorges Dam fully operational, science‐based adaptive strategies are urgently needed to avoid catastrophic ecological consequences. This study quantified the link between water level variation and population growth rate of the Siberian crane in Poyang Lake using a suite of advanced statistical techniques. We first used the stochastic Gompert growth model within the state space modelling (SSM) framework to infer population growth rate, density dependence, and process variability and observation errors. We then applied generalized additive models (GAMs) to the population growth rate to quantify the effects of environmental stochasticity. Our SSM results indicated that there was little support for density dependence, and environmental stochasticity was the main forcing for Siberian crane population variations in Poyang Lake. Although the SSM suggested that water levels in both high‐ and low‐water seasons were important factors for Siberian crane population, inference on their effects were elusive because of large confidence intervals of the estimated coefficients. Using GAM, we confirmed the non‐linear effects of water level on population growth rate. Based on the modelled response curves, we proposed the optimal water level for Siberian crane conservation: (a) maximum summer water season level should be less than 19.5 m and (b) minimum winter water level should be between 8.7–10.2 m. Our methods of integrating population dynamic model and GAM have wide relevance for regional biological conversation efforts that seek to maintain a resilient population of threatened species. Copyright © 2014 John Wiley & Sons, Ltd.