A Preliminary Research On Numerical Simulation Of Aerodynamic Effect When High-Speed Train Out From Tunnel Under Strong Wind Condition

The Trains will cause strong wind when in out from tunnel, and the aerodynamics is verycomplexity. If the train encounter strong environmental wind when it out from tunnel, theaerodynamics will more complexity and the vehicle dynamics will be worsen, the safety inoperation will be challenged. Our country is rich in land and wind resources. The north westregion appear strong wind perennial, existed Lanxin’s railway often lead to train arrival lateby strong wind. If the wind step is large, the strong wind will caused the train overturned. Thecoming Lanxin high-speed railway will through Gansu province and Qinghai province andXinjiang province, and it will through famous five wind zone. The coming Lanxin high-speedrailway is1776km, the579.599km is among strong wind zone, account for32.8%. The linehave462.409km lies in strong wind zone in Xinjiang province account for64.8%of the linebelong to Xinjiang province. The number of tunnel locate in the wind zone is11. So theresearch of the train out from tunnel under strong wind condition is very necessary.We select the CRH2high speed train have bogie and pantograph flow guiding cover andwindshield to simulate. The tunnel portal is brim cutting type. The train and the tunnelgeometry is complex, so we generat the Tetra mesh around the train and in the computationaldomain. We used ASI technique to modeling the train out from tunnel, the two side of glideplane is very important, so we used Hexa in the two side of the glide plane. We merge theTetra and the Hexa in the ICEM-CFD software. We used the STAR-CD software to modelingand calculate. To avoid the unreasonable physical phenomena in numerical simulation, asmooth start method is used. The high Reynolds number SST model is used. Based on thereasonable boundary conditions and initial conditions, PISO algorithm was used to solve theReynolds averaged equations, and CD scheme was used to the diffusion term, and MARSscheme was used to the convective term. The resulted algebraic equations were solved byusing the CG method. Based on the above ways, we modeling the overall process of train outfrom tunnel under strong wind condition.The article research the pressure of train surface, and the changing process of the sideforce and the lift force and the overturning moment when Train out from tunnel under the30m/s wind condition at the speed200km/h. We also research the flow field variation out oftunnel under this condition. Compares the side force and the lift force and the overturningmoment when Train out from tunnel under the30m/s and60m/s wind condition at the speed200km/h and220km/h and250km/h. Obtained the impact of train speed and wind speed tothe flow field. The mesh merge skill can give a hand to the follow study for the more realistictrain model. The result of the modeling can provide a beneficial reference to the follow study.