Numerical Simulation Of The Flow And Wake Flow Around High-speed Trains

Beijing-Tianjin and Wuhan-Guangzhou passenger line have been opened one after another. Train speed over 350km/h of the passenger transport has become an inevitable trend in the future. With the rising rate of high-speed train, the various aerodynamic phenomena become more prominent and the aerodynamics problem has become a key technical issue of the high-speed EMU.The flow around high-speed train in aerodynamics is actually complicated flow around a blunt body and it has a complex nature with mass separation, attachment again, unsteady vortex shedding in the turbulent wake and etc. As a basis for flow around blunt bodies authentication, this paper first made numerical simulation study of flow around a cylinder, which made the author studied the STAR-CD in one deeper way. Secondly, using high Reynoldsk-εmodel with the combination of the wall function and RSM model to simulate the 2D hill flow. The shape of the hill is as the same as the have of the CRH3. As a result, the study of the hill flow would provide some basic experience and methods to the later studies.Using high Reynolds number k-εmodel with three different sets of block structured computational grids to computed the simplified high speed train under the influence of crosswind. It carried out the independence of the grid to the flow around simplified high speed train. The force coefficient around the body in three directions and the surface pressure coefficient around the train body were obtained. It had analyzed the flow field characteristics, compared the results of the experiment data, and found that the results were basically consistent. By using the post-processing software, such as Fieldview, we obtained the streamlines on the train body and the details of the wake flow. This paper secondly simulated the simplified ICE2 high speed train under the 30°side wind with high Reynolds number k-εmodel. The force coefficient around the body in three directions and the surface pressure coefficient around the body were obtained. It had analyzed the flow field characteristics and found that the results were basically consistent. Through the comparison with literature, it had proved that the calculation method is reasonable on the commercial software STAR-CD platform, again.On the basis of the simulation of the simplified high speed train and ICE2 model, this paper had further simulated the CRH3 EMU real 1:1 car model under the influence of 30°side wind and crosswind. Because the geometry of the CRH3 EMU model is very complicated, it is much difficult to use structured grid to create the mesh around it. At present, there was almost a little even no specialist to study it with structured grid, most of the results were unstructured grid. The author got over many difficulties and used the structured grid to create mesh around CRH3 model. Compared with the unstructured grid, the structured grid has more advantages in modeling three dimensions separate flows. Using high Reynolds k-εmodel to simulate the CRH3 EMU model in two different side wind, it had analyzed the differences between the two turbulence models, and the flow velocity distribution under the typical velocity of 350km/h,the pressure distribution on the train surface,the resistance distribution in each carriage. This paper also analyzed the same parameters as the typical velocity of 350km/h; the conclusions provided some useful basis for the future research works of the numerical simulation of high-speed train.