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761.
上海城市轨道交通网络建设与资源共享 总被引:13,自引:4,他引:9
顾伟华 《城市轨道交通研究》2005,8(6):15-19
介绍了上海城市轨道交通建设的现状和近、远期的发展规划、鉴于国外城市轨道交通发展的经验和上海城市轨道交通即将成网的现实,就人力、土地、运营设备与设施、检修设备与设施、施工机具与设施等5个方面,提出了上海城市轨道交通网络资源共享的基本构想和初步方案。 相似文献
762.
On the basis of the transient water wave (TWW) theory, focused wave is generated in the circulating water channel. Numerical simulation of the focused wave is carried out by solving the Reynolds averaged Navier-Stokes (RANS) equations. The dynamic grid technique is adopted to simulate the motion of the wave maker, and the volume of fluid (VOF) method is used to capture the free surface of the wave. The simulation results are compared with the measured data, and good agreement is obtained. For quantitative estimation of the numerical simulation error and uncertainty, the uncertainty analysis method recommended by the International Towing Tank Conference (ITTC) procedure is performed for the simulation results of the surface elevations at different positions. Both grid-convergence and time-step-size convergence studies are conducted using three types of grids and time step sizes. The simulation results are all monotonously convergent in the verification procedure, and the validations of the simulated surface elevations with the positions at 3.5, 4.0 and 4.5m are all achieved by comparing with the validation uncertainty. It is found that the numerical simulation errors caused by the grid and time-step-size in the convergence studies have the same order of magnitude. In addition, the numerical errors and uncertainties for the surface elevations at different positions are compared and discussed in detail. This paper presents the first attempt to carry out the uncertainty analysis of the simulation of focused wave, and the effectiveness of the proposed verification and validation procedures in the uncertainty analysis is demonstrated. 相似文献
763.
In order to assess the influence of ship-bank interaction on ship manoeuvring motion, planar motion mechanism (PMM) tests on a scale model of the KRISO very large crude carrier (KVLCC2) are conducted in different water depths in circulating water channel (CWC). The asymmetric hydrodynamic derivatives are defined to characterize the bank effect, and they are measured through the straight towing test with varying lateral displacements. The linear and nonlinear hydrodynamic derivatives are determined from the test data of the Fourier integral and mathematical regression model. The rudder and heading angles required at equilibrium conditions in different ship-bank distances are calculated by the manoeuvring model. The directional stability with varying ship-bank distances is studied in terms of eigenvalue analysis. Analysis based on the test results shows that the KVLCC2 model ship appears inherently unstable for keeping course in deep and shallow water conditions. When the ship-bank distance decreases, the increasing ship-bank interaction can dramatically affect some parameters of the criteria for course keeping. 相似文献
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旋挖钻机电子控制技术研究概况 总被引:1,自引:0,他引:1
在公路、铁路和市政建设等重大基础建设工程中,钻孔灌注桩施工作为一种主要的施工方法得到了广泛的应用。其中,旋挖钻机以其装机功率大、输出扭矩大、轴向压力大、施工效率高、机动灵活等诸多优点受到业内人士的普遍青睐,逐渐成为钻孔灌注桩成孔作业的首选施工设备。 相似文献
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对客车底盘平台优化方案的量化方法进行初步探讨,着重介绍利用市场因素的影响、集体决策方法、量化评分等来改善目前的底盘平台优化决策方式。 相似文献