STUDY ON CARGO FLOW PROJECTION IN TUMEN RIVER ECONOMIC DEVELOPMENT AREA

The paper studies the methodologies of the cargo flow study and projections in Tumen River Economic Development Area(TREDA) that some governments and international scholars used. The authors consider that, in order topromote investment, facilitation of cross-border trade and infrastructure in the region, the basic methodology should bebased on the regional economic growth of pertinent Northeast Asian countries and regions to make projections of the situations of regional cargo flows, and then analyzing the cargo flow trend. Based on the above, the authors utilize the routescomparing model and gravity model to forecast the cargo flows through the ports and related routes in TREDA (2000 -2020). The authors also inquire into the main obstacles which affect the cargo flows of the region, analyze the influenceson cargo flows if the obstacles change with sensitivity analyses and try to find the way to sole the obstacles.

A consistent projection-based SUPG/PSPG XFEM for incompressible two-phase flows

In this paper, a consistent projection-based streamline upwind/pressure stabilizing Petrov-Galerkin （SUPG/PSPG） extended finite element method （XFEM） is presented to model incompressible immiscible two-phase flows. As the application of linear elements in SUPG/PSPG schemes gives rise to inconsistency in stabilization terms due to the inability to regenerate the diffusive term from viscous stresses, the numerical accuracy would deteriorate dramatically. To address this issue, projections of convection and pressure gradient terms are constructed and incorporated into the stabilization formulation in our method. This would substantially recover the consistency and free the practitioner from burdensome computations of most items in the residual. Moreover, the XFEM is employed to consider in a convenient way the fluid properties that have interfacial jumps leading to discontinuities in the velocity and pressure fields as well as the projections. A number of numerical examples are analyzed to demonstrate the complete recovery of consistency, the reproduction of interfacial discontinuities and the ability of the proposed projection-based SUPG/PSPG XFEM to model two-phase flows with open and closed interfaces.

Model of Cost-benefit Flow in Six Green Projects in China

From the point of cost-benefit flow and with the Six Green Projects in China as the case and background, it is criticized that the current natural resource and environmental management and the policies in China have some problems unsolved since the model of cost-benefit flow is still centralized and mainly in an administrative way in spite of many efforts made theoretically and practically. It is suggested that a new model based on market-oriented economy from the point of cost-benefit flow with Six Green Projects Management and Policies System consist of complete natural reserve (NR). Management system included environmental nature reserves in addition to biodiversity nature reserve, paid using nature resources, an environmental conservation and construction industry and renewable resource production incentive system that turn the direct administration and operation to management and services. The detail figure of the new model of cost-benefit flow is provided and the main points related are discussed in this paper.

Model reduction for supersonic cavity flow using proper orthogonal decomposition(POD)and Galerkin projection

The reduced-order model （ROM） for the two-dimensional supersonic cavity flow based on proper orthogonal decomposition （POD） and Galerkin projection is investigated. Presently, popular ROMs in cavity flows are based on an isentropic assumption, valid only for flows at low or moderate Mach numbers. A new ROM is constructed involving primitive variables of the fully compressible Navier-Stokes （N-S） equations, which is suitable for flows at high Mach numbers. Compared with the direct numerical simulation （DNS） results, the proposed model predicts flow dynamics （e.g., dominant frequency and amplitude） accurately for supersonic cavity flows, and is robust. The comparison between the present transient flow fields and those of the DNS shows that the proposed ROM can capture self-sustained oscillations of a shear layer. In addition, the present model reduction method can be easily extended to other supersonic flows.

AN IMPLICIT SOLUTION OF BI-PENALTY APPROXIMATION WITH ORTHOGONALITY PROJECTION FOR THE NUMERICAL SIMULATION OF BINGHAM FLUID FLOW

An implicit algorithm of Bi-penalty approximation with orthogonality projection for the numerical simulation of Bingham fluid flow problems is proposed in this paper. A Newton fluid flow with two kinds of artificial viscosity subjected to the inequality constraint is introduced to approximate the Bingham fluid flow. This approach can effectively simulate the Bingham fluid flow with floating rigid cores or fixing rigid cores.

A Kinematics Scalar Projection Method (KSP) for Incompressible Flows with Variable Density

A new scalar projection method presented for simulating incompressible flows with variable density is proposed. It reverses conventional projection algorithm by computing first the irrotational component of the velocity and then the pressure. The first phase of the projection is purely kinematics. The predicted velocity field is subjected to a discrete Hodge-Helmholtz decomposition. The second phase of upgrade of pressure from the density uses Stokes’ theorem to explicitly compute the pressure. If all or part of the boundary conditions is then fixed on the divergence free physical field, the system required to be solved for the scalar potential of velocity becomes a Poisson equation with constant coefficients fitted with Dirichlet conditions.

Velocity Projection with Upwind Scheme Based on the Discontinuous Galerkin Methods for the Two Phase Flow Problem

The upwind scheme is very important in the numerical approximation of some problems such as the convection dominated problem, the two-phase flow problem, and so on. For the fractional flow formulation of the two-phase flow problem, the Penalty Discontinuous Galerkin (PDG) methods combined with the upwind scheme are usually used to solve the phase pressure equation. In this case, unless the upwind scheme is taken into consideration in the velocity reconstruction, the local mass balance cannot hold exactly. In this paper, we present a scheme of velocity reconstruction in some H(div) spaces with considering the upwind scheme totally. Furthermore, the different ways to calculate the nonlinear coefficients may have distinct and significant effects, which have been investigated by some authors. We propose a new algorithm to obtain a more effective and stable approximation of the coefficients under the consideration of the upwind scheme.

Water Vapor Transport and Cross-Equatorial Flow over the Asian-Australia Monsoon Region Simulated by CMIP5 Climate Models

The summer mean water vapor transport （WVT） and cross-equatorial flow （CEF） over the Asian- Australian monsoon region simulated by 22 coupled atmospheric-oceanic general circulation models （AOGCMs） from the World Climate Research Programme＇s Coupled Model Intercomparison Project Phase 5 （CMIP5） were evaluated. Based on climatology of the twentieth-century simulations, most of models have a reason- ably realistic representation of summer monsoon WVT characterized by southeast water vapor conveyor belt over the South Indian Ocean and southwest belt from the Arabian Sea to the East Asian. The correlation coefficients between NCEP reanalysis and simulations of BCC-CSMI-1, BNU-ESM, CanESM2, FGOALS-s2, MIROC4h and MPI-ESM-LR are up to 0.8. The simulated CEF depicted by the meridional wind along the equator includes the Somali jet and eastern CEF in low atmosphere and the reverse circulation in upper atmosphere, which were generally consistent with NCEP reanalysis. Multi-model ensemble means （MME） can reproduce more reasonable climatological features in spatial distribution both of WVT and CEF. Ten models with more reasonable WVT simulations were selected for future projection studies, including BCC- CSMI-1, BNU-ESM, CanESM2, CCSM4, FGOALS-s2, FIO-ESM, GFDL-ESM2G, MRIOCS, MPI-ESM-LR and NorESM-1M. Analysis based on the future projection experiments in RCP （Representative Concentra- tion Pathway） 2.6, RCP4.5, RCP6 and RCP8.5 show that the global warming forced by different RCP scenarios will results in enhanced WVT over the Indian area and the west Pacific and weaken WVT in the low latitudes of tropical Indian Ocean.

Simulation of Unsteady Water Film Flow on Pelton Bucket

In order to simulate the complicated unsteady flow in Pelton bucket, it is necessary to apply the animated cartoon approach. In this paper, a free jet and the inner surface of a bucket is described by boundary fitted grid (BFG) with non-orthogonal curvilinear coordinates. The water flow is discretized in space and time for CFD (computational fluid dynamics). The moving grids of water film are successfully projected onto the bucket’s inner surface by a projection algorithm. The visualization result of the jet landing on bucket’s surface and the unsteady flow in the rotating buckets in 3D verifies the effectiveness of the proposed method.

Structure and Flow Characteristics of Flat Fan Nozzles with a Single Orifice Formed by a Rectangular Cut

The flat fan nozzle with a single orifice formed by a rectangular cut at the nozzle exit through a semi-ellipsoid blind end was developed. The flow rate characteristic of the nozzle was analyzed. Theoretical analysis shows that the discharge coefficient of the nozzle is a function of the ratio of the projected exit flow area to the cross sectional area of the nozzle input section. Water spraying experiment results show that the discharge coefficient increases with the increase of the ratio of the projected exit flow area to the cross sectional area of the nozzle input section when the rectangular cut depth doesn't exceed the distance from the center of the hemisphere to the nozzle end; conversely,the discharge coefficient decreases with the increase of the ratio; for a given nozzle,the discharge coefficient varies with Reynolds number.

Joint optimization scheduling for water conservancy projects incomplex river networks

In this study, we simulated water flow in a water conservancy project consisting of various hydraulic structures, such as sluices, pumping stations, hydropower stations, ship locks, and culverts, and developed a multi-period and multi-variable joint optimization scheduling model for flood control, drainage, and irrigation. In this model, the number of sluice holes, pump units, and hydropower station units to be opened were used as decision variables, and different optimization objectives and constraints were considered. This model was solved with improved genetic algorithms and verified using the Huaian Water Conservancy Project as an example. The results show that the use of the joint optimization scheduling led to a 10% increase in the power generation capacity and a 15% reduction in the total energy consumption. The change in the water level was reduced by 0.25 m upstream of the Yundong Sluice, and by 50% downstream of pumping stations No. 1, No. 2, and No. 4. It is clear that the joint optimization scheduling proposed in this study can effectively improve power generation capacity of the project, minimize operating costs and energy consumption, and enable more stable operation of various hydraulic structures. The results may provide references for the management of water conservancy projects in complex river networks.

Numerical Modelling and Simulation of Sand Dune Formation in an Incompressible Out-Flow

In this paper, we are concerned with computation of a mathematical model of sand dune formation in a water of surface to incompressible out-flows in two space dimensions by using Chebyshev projection scheme. The mathematical model is formulate by coupling Navier-Stokes equations for the incompressible out-flows in 2D fluid domain and Prigozhin’s equation which describes the dynamic of sand dune in strong parameterized domain in such a way which is a subset of the fluid domain. In order to verify consistency of our approach, a relevant test problem is considered which will be compared with the numerical results given by our method.

基于Moldflow的玩具汽车外壳注塑方案对比分析

以某品牌玩具汽车外壳为例,采用Moldflow模流分析软件,对不同浇口数量条件下的最佳的浇口位置进行分析。同时,对比三种不同的注塑方案,对充填速度、压力分布、注射位置处压力、气穴位置、流动前沿温度、熔接线数量、收缩率以及翘曲值等参数的影响进行仿真分析。结果显示:该品牌玩具汽车外壳采用单浇口的注塑方案效果最好。

Ensemble projections of climate and streamflow in a typical basin of semi-arid steppes in Mongolian Plateau of 2021-2100

The Kherlen River is the main water source for Hulun Lake,the largest lake in northern China.Due to reduced inflow from the Kherlen River,Hulun Lake experienced rapid shrinkage at the beginning of the 21st century,posing a serious threat to the ecological security of northern China.However,there is still a significant lack of projections regarding future climate change and its hydrological response in the Kherlen River basin.This study analyzed the projected climate and streamflow changes in the Kherlen River basin,a vital yet vulnerable international semi-arid steppes type basin.A combination of multi-model ensemble projection techniques,and the soil and water assessment tool(SWAT)model was employed to examine the spatio-temporal changes in precipitation,temperature,streamflow,and the associated uncertainties in the basin.The temperature(an increase of 1.84-6.42℃)and the precipitation(an increase of 15.0-46.0 mm)of Kherlen River basin are projected to increase by 2100,leading to a rise in streamflow(1.08-4.78 m^(3) s^(-1)).The upstream of the Kherlen River exhibits remarkable increasing trends in precipitation,which has a dominant influence on streamflow of Kherlen River.Noteworthy increases in streamflow are observed in April,August,September,and October compared to the reference period(1971-2000).These findings suggest a partial alleviation of water scarcity in the Kherlen River,but also an increased likelihood of hydrological extreme events.The projected temperature increase in the Kherlen River basin exhibits the smallest uncertainty,while more pronounced uncertainties are found in precipitation and streamflow.The spread among the results of CMIP6 models is greater than that of CMIP5 models,with lower signal-to-noise ratio(SNR)values for temperature,precipitation,and streamflow.

Multi-Mode Resource Constrained Project Scheduling Models for Progress and Equal Time Interval Payments

This study utilizes a time-precedence network technique to construct two models of multi-mode resource constrained project scheduling problem with discounted cash flows （MRCPSPDCF）, individually including the progress payment （PP） and the payment at an equal time interval （ETI）. The objective of each model is to maximize the net present value （NPV） for all cash flows in the project, subject to the related operational constraints. The models are characterized as NP-hard. A heuristic algorithm, coupled with two upper bound solutions, is proposed to efficiently solve the models and evaluate the heuristic algorithm performance which was not performed in past studies. The results show that the performance of proposed models and heuristic algorithm is good.

溢洪道弯道段流态改善试验研究和应用

溢洪道泄槽弯道泄流时,弯道段内易产生横向冲击波,水流紊乱,流态较差,会不同程度地影响溢洪道的正常运行。该文根据广东省部分水库陡槽溢洪道水力模型试验研究成果,介绍改善溢洪道泄槽弯道段流态的断面超高、斜向高低坎、纵向导流墙、阶梯跌坎、弯道前设置消力池等工程措施,并对各种工程措施的适用性进行分析,研究成果可供类似工程设计和运行参考。

国家重大项目管理应用技术就绪度评价的实施方案及优化——基于“工厂化农业关键技术与智能农机装备”国家重点专项的案例研究

技术就绪度(TRL)评价是建立在项目分解结构和关键技术元素识别基础上的,强调了技术在不同发展阶段之间的转化,能够更直观展现专项实施进展和目标完成情况,并通过进一步丰富技术研发各阶段的评价细则创新项目管理。现阶段已经形成了比较成熟的TRL9级定义,但以应用于工业领域为主,在管理层面衡量科技项目的成效尚未涉及。鉴于此,结合“工厂化农业关键技术与智能农机装备”国家重点专项的项目特点开展TRL管理方法案例研究。梳理TRL概念发展和国内外研究与应用状况,系统梳理“原理构想—技术验证—模拟环境测试—实际应用”这一研发链条,从TRL审查组、被评单位和评价对象3个关键要素入手,从技术指标、技术成果与创新性指标、应用指标3个维度构建覆盖技术、技术成果与创新性评估及应用效能的技术就绪度评价体系,并在考量评价组织机构的运作特性基础上,运用专家咨询法设计技术就绪度评价流程,分别从技术就绪度审查组和被评单位两个层面形成操作规范,构建符合该专项特点的TRL一般标准、TRL指标体系、评级要点参考指标,最终建立“工厂化农业关键技术与智能农机装备”重点专项项目的技术就绪度管理方法。根据所提出的TRL评价实施方案,进一步从开展农业领域应用试点和推广、加强评价方法普及和操作培训、促进与其他项目管理方法有效融合以及加快信息化应用和技术开发等方面,思考提出促进TRL在科技项目管理中高质量实施的建议。

推进长江流域已建水利水电工程生态流量保障与管理的思考

河湖生态流量保障是维持河湖生命、复苏河湖生态环境的重要举措,是贯彻落实习近平生态文明思想的重要内容。水利水电工程在水资源调配、保障河湖生态流量、复苏河湖生态环境方面具有重要作用。在分析长江流域重点河湖生态流量保障与管理工作成效的基础上,总结归纳已建水利水电工程生态流量保障与管理存在目标核定难度大、生态流量认识不统一、监控能力不足等主要问题。以问题为导向,以保障河湖生态流量为目标,以强化水利水电工程调度保障为手段,坚持流域统筹、系统推进,因地制宜、分区分类,问题导向、健全措施,部门协同、形成合力,提出推进已建水利水电工程生态流量保障与管理的总体思路。围绕生态流量目标核定、监测预警、泄放设施完善、统一调度、部门协调、经费保障,提出深入推进已建水利水电工程生态流量保障与管理的对策建议,为维护流域河湖生态系统健康及推动长江经济带水利高质量发展提供支撑。

Fine-Grained Work Element Standardization for Project Effort Estimation

Traditional project effort estimation utilizes development models that span the entire project life cycle and thus culminates estimation errors. This exploratory research is the first attempt to break each project activity down to smaller work elements. There are eight work elements, each of which is being defined and symbolized with visually distinct shape. The purpose is to standardize the operations associated with the development process in the form of a visual symbolic flow map. Hence, developers can streamline their work systematically. Project effort estimation can be determined based on these standard work elements that not only help identify essential cost drivers for estimation, but also reduce latency cost to enhance estimation efficiency. Benefits of the proposed work element scheme are project visibility, better control for immediate pay-off and, in long term management, standardization for software process automation.

基于多项式混沌展开的交直流系统全纯嵌入概率潮流计算方法

为快速、准确量化分析风电出力不确定性对交直流电力系统潮流分布的影响,提出一种基于多项式混沌展开(PCE)的交直流电力系统全纯嵌入概率潮流计算方法。该方法首先根据风电出力的概率分布特征选择最优正交基函数,构造近似风电出力概率分布特征的PCE表达式;其次,将该PCE表达式引入交直流电力系统的全纯嵌入潮流方程中,构建基于PCE的交直流电力系统全纯嵌入概率潮流计算模型;再次,通过Galerkin投影将所构建的全纯嵌入概率潮流计算模型转化为高维确定性全纯嵌入潮流计算模型;然后,借助确定性全纯嵌入潮流模型求解方法,实现对所转化的高维确定性全纯嵌入潮流模型的求解,并根据所得PCE逼近系数计算交直流电力系统潮流的概率分布特征;最后,通过修改的PJM 5节点、IEEE 30节点和IEEE 118节点交直流测试系统算例验证所提方法的准确性和有效性。