Simulation Research Of Aerodynamics Trains Critical The Tunnel Intersection Length

With the rapid development of high-speed railway, China has marched towards a high-speed rail era. One of its goals is to achieve high-speed rail transport. But for railway technology, the high speed has brought a lot of practical issues, one of which is aerodynamics. Thus, the tunnel intersection, as part of the train aerodynamics research, has attracted more and more attention.This thesis refers to the basic principles and theories of computational fluid dynamics, describes the problems concerning computational fluid dynamics and introduces methods and theories involved in the numerical calculation. In addition, the paper also cites the calculations of train tunnel length during critical intersection employed by China Academy of Railway Sciences, and lists the possible theoretical domestic train tunnel length during critical intersection.Based on the needs of simulation, this thesis selects the appropriate geometry, computational domain, boundary conditions and mathematical model, establishes a two-dimensional computational model of train’s critical intersection, and meshes the calculation model. On the basis of information provided by China Academy of Railway Sciences, the author validates the established model of by comparing the simulating calculation data with the actual vehicle test data, proving that the simulation data is authentic.This thesis selects the most common domestic operations intersection with a speed between300km/h-300km/h to simulate under the conditions of300m,500m,700m,750m,800m,816m,850m,900m,1100m and1300m and finally obtains the pressure wave curve and data set at the control points of train’s body surface. According to the processing of the simulation data, the author makes the comparison and analysis by selecting each a point on truck and trailer, collects the statistic of the minimum data, the maximum data and amplitude of the pressure wave under the above conditions, and establishes a relationship graph of changes in the magnitude and the length of the tunnel. The conclusion can be drawn that through analysis changes in the two monitoring points maximum under the train intersection at810m to825m. Thus, the simulation verifies the correctness of calculating the tunnel length by the methods of train intersection theory. In addition, this thesis has summarized the pressure cloud and grid when the EMU enters the tunnel, intersection and out of the tunnel.