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161.
横向风作用下高速铁路车桥系统绕流特性分析 总被引:6,自引:3,他引:6
基于不可压缩二维雷诺平均N-S方程,采用RING(renormalization group)k-ε两方程湍流模型,对德国ICE(intercity-express)列车和标准简支梁组成的车桥系统在横向风作用下的二维绕流特性进行了分析.计算网格为由三角形非结构网格和四边形结构网格组成的混合网格,采用有限体积法对微分方程进行离散,应用SIMPLE算法解决压强-速度耦合关系.根据高速铁路桥梁带挡风墙的特点,引入空腔流动研究成果对车桥系统的绕流特性进行了理论分析.结果表明,高速铁路桥梁挡风墙的挡风机理在于充分运用了空腔流的旋涡特性. 相似文献
162.
类客车体绕流场的数值模拟 总被引:1,自引:0,他引:1
应用计算流体力学专业软件PHOENICS,从雷诺时均N-S方程出发,采用k-ε湍流模型,对类客车体外型的三维绕流场进行数值模拟,着重研究了后体收缩尾段的上表面倾斜角对底部流动的影响。 相似文献
163.
上海市联运总公司是在原上海市联运总公司、原上海市汽车运输代理公司(暨上海公路货运配载中心)、原上海市通联运输实业总公司三家货运代理企业基础上及由其原三家企业投资组建的上海爱尔思国际货运公司,按上海交运(集团)公司“拓展、创新、增强”的发展战略于1997年9月经资产重组而新建的新型货代联运企业。 相似文献
164.
165.
溃坝模拟的光滑粒子流体动力学方法及其粘性特性(英文) 总被引:1,自引:0,他引:1
Smoothed particle hydrodynamics (SPH) is a Lagrangian meshless particle method. It is one of the best method for simulating
violent free surface flows in fluids and solving large fluid deformations. Dam breaking is a typical example of these problems.
The basis of SPH was reviewed, including some techniques for governing equation resolution, such as the stepping method and
the boundary handling method. Then numerical results of a dam breaking simulation were discussed, and the benefits of concepts
like artificial viscosity and position correction were analyzed in detail. When compared with dam breaking simulated by the
volume of fluid (VOF) method, the wave profile generated by SPH had good agreement, but the pressure had only reasonable agreement.
Improving pressure results is clearly an important next step for research. 相似文献
166.
Experiments were conducted to study characteristics of flow when flow is fluctuating. The experimental results showed a phase
difference between the flow rate and the pressure drop fluctuations. This phase difference between the fluctuating flow rate
and pressure drop was analyzed for laminar flow. Analysis showed that the phase difference changes with the period of the
flow fluctuation, the pipe radius, the density and the dynamic viscosity of the liquid. Fluctuating pipe flow was then numerically
simulated. Results of the numerical simulation were compared with theoretical values and experimental results. It was shown
that, when the flow rate fluctuates with time as a sine wave, the pressure drop fluctuates with the same periodicity, and
there is a phase difference between them. 相似文献
167.
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169.
Two-phase flow pressure drop measurements were made during the phase change heat transfer process of R22 in a small horizontal smooth tube with 2.5 mm inside diameter. Conclusions can be drawn that the quality corresponding to the pressure gradient peak value of small tubes became higher than that of large tubes. The effect of quality to pressure drop becomes weak as the mass flux increases. The experiment data were compared with the predicated values of the state-of-the-art correlations from the open literature. The comparisons between the data and the predictions indicate that most of the state-of-the-art correlations fails to predict the experimental data.Chisholm model shows a relatively better predictive ability than the other empirical correlations although it has a mean deviation of 26.7%. But the predicated values of Chisholm model are lower by 50% than the experimental data when the quality becomes larger. 相似文献
170.