Aerodynamic Effects On Car Body And Side Windows When High-speed Trains Passing Each Other In Tunnel

When high-speed trains passing each other in a short tunnel, because of the influence of the tunnel space limit and portal effect, train in the tunnel intersection of pneumatic change is more complex and intense compared to the open wire passing. Excessive pneumatic impact can result in the destruction of the train rigid body structure, train derailment, side window fragmentation, which is a serious threat to the safe operation of trains. Therefore, study on aerodynamic characteristics on high-speed train meeting in tunnel is necessary.In this paper, numerical simulation is used as the main research means, based on the three dimensional unsteady compressible Navier-Stokes equations and the standard of k epsilon turbulence model, using the finite volume method to conduct a comprehensive analysis of the flow field in the high-speed train meeting in tunnel. By simulating different conditions, a more detailed analysis of the speed of trains passing, tunnel length, Cross-sectional area, location of two trains meeting, buffer structure and influencing factors of the high-speed train meeting in the tunnel process bodywork surface pressure and aerodynamic changes. Under various operating conditions on pressure wave on the detailed study is made on the influence of the side window, the pressure pulse train aerodynamic force and surface pressure is obtained and the relationship between various influencing factors.The results show that the high-speed train meeting in the tunnel process appeared intense pressure fluctuations, train surface pressure of the different locations have the same trend. Head car tip of maximum pressure changes, pressure changes along the front to the rear of the direction gradually decreasing, and train wall is mainly affected by negative pressure, when the side window failure occurs, it will be sucked out. In non-rendezvous time, the train on both sides of the pressure is substantially the same, as the rendezvous side of the rendezvous process pressure change is greater than the non rendezvous side pressure changes, wherein the rendezvous side of the first train side window position by the negative pressure of the largest absolute.The same trend of change of air resistance of high-speed trains and train surface pressure changes, and the changes in the rates are relatively close, the lateral force and lift changes is determined mainly by the speed of the train, it has little to do with other factors. High-speed trains through the tunnel process subject to greater air resistance and lateral force, while relatively small changes in the lift. Two trains passing each other in tunnel middle point of pressure wave is most intense, train in the500m long tunnel midpoint when passing the biggest air resistance more open wire passing increased by nearly248%. EMU section of each train by the aerodynamic force of change is not the same, the first car of aerodynamic force change is biggest, tail of trains, the middle trains is minimal. Buffer structure can effectively decrease the surface pressure of train and air resistance changes, but little impact on pressure amplitude value of the main factors affecting the safety of side window for the side window of extreme pressure and pressure gradient.