快速公交系统(BRT)在我国的发展研究

快速公交系统(BRT)作为一种新的交通方式,在世界各城市得以快速推广。本文简单介绍了它的特点,对BRT在我国发展的主要问题发表了自己的看法并给出了相应的建议。     

基于Matlab的平均加速度法求解二自由度动力方程的误差分析

Newmark算法是求解结构动力学问题的主要方法之一,其精确度取决于时间步长h和最短固有周期T的比值^h/T_min[1],对于已知最短固有周期T的系统,其精确度只与时间步长h有关。当Newmark算法的积分参数gama为1/2、beta为1/4时被称为平均加速度法[2],本文主要分析了平均加速度法与simulink中runge—kutta45算法的相对误差及绝对误差,验证了平均加速度法在步长为0.001时,可以达到所做项目的精度要求,本项目要求精度为千分之三。     

Three-dimensional hydrostatic modeling of a bay coastal area

This article describes the development of a three-dimensional (3D) multilayer hydrostatic model of tidal motions in the Ariake Sea and its application. The governing equations were derived from 3D Navier-Stokes equations and were solved using the fractional step method, which combines the finite difference method in the horizontal plane and the finite element method in the vertical plane. This study introduced a 3D, time-dependent, hydrostatic, tidal current model that can compute wetting and drying in tidal flats due to tidal motion. The 3D model was first tested against analytical solutions for three standard cases in a rectangular basin in order to investigate the performance of the model. Then, the model was applied to Saigo fishery port and the Ariake Sea. For standard cases, the numerical solutions were almost identical to the analytical solutions. Finally, the model results for Saigo port and the Ariake Sea show good agreement with the field observations.