Influence Research Of Lateral Excursion Of High-speed Vehicle Induced By Air Pressure

With the increasing of vehicle travelling speed, to which aerodynamics problems related are becoming more and more prominent. Particularly, the vehicle passing pressure wave and the influence of lateral air pressure are the main factors affecting vehicle’s safe operation. The lateral force and the later moment are the main dynamic responses of high-speed vehicle with air load acting on. The influences of the aerodynamic forces including lateral air pressure and passing pressure wave on the lateral excursion of vehicle are studied to ascertain the influential characteristics, which is of great significance to maintain the safety and high speed of vehicle. Meanwhile, the suggestions about optimizing the dynamic envelope line of high-speed vehicle are proposed.CRH3typed vehicle is considered as the research object in the dissertation. Through the combination of fluid dynamics and vehicle’s structural dynamics, the dynamic analytical software of ANSYS-CFX is adopted to calculate the effect of external factors involving lateral air pressure and passing pressure wave on the lateral dynamic excursion of the operation vehicle. The surface structuring meshing is conducted for the vehicle model by application of the module relating to structural dynamics in ANSYS. And the dynamic meshing of CFX solver is applied to simulating the fluid-solid coupling effect of vehicle and air. Besides, the numerical simulation analysis is conducted for the interacting vehicle and air-flow field under different working condition.Based on the calculation results under the condition of different external air-flow field, it can be seen that when the high-speed vehicle is on operation, the action of lateral air pressure and passing pressure wave affects the lateral safety of vehicle. The impact is closely related to the vehicle speed, lateral air speed, space between passing vehicles and superrelation on curve, etc. The lateral excursion is gradually increasing with the growing air load and vehicle speed. When the air speed increases by over25m/s, the high-speed vehicle is likely to exceeding the gauge even overturning. When the high-speed vehicle is passing through curve section, the external air load will have an evident effect on the lateral excursion of vehicle. In order to determine the reasonable curve radius and superrelation of outer rail, the air load and the vehicle speed should be comprehensively taken into account. The appropriate increase of space between passing vehicles can effectively reduce the passing pressure wave thus lessening its lateral effect on vehicle. With consideration of the external air-flow field, the suggestions about optimizing the dynamic envelope line of high-speed vehicle are proposed.