Research On 1-D And 3-D Coupling Of The Micro-Pressure Wave At The Long Tunnel Outlet

High-speed railway has been regarded as a good modern transportation way which takes the advantages of rapid, safety and punctual,high carrier volume, low carbon environmental and economic benefits.Now it has become an important symbol in contemporary society.It is difficult to imitate practical situation whether aerodynamics effects model test or numerical simulation due to aerodynamics effects caused by high-speed railway passing the long tunnel.The vehicle tests cost too much, and the tests could not be completed until tunnel is constructed.Therefore it is necessary to seek an economical and efficient numerical calculation method.This thesis adopts the advantages of 1-d algorithm and 3-d algorithm, and couples with 1-d calculation and 3-d calculation, proposed a micro-pressure wave calculation method at the long tunnel outlet. The major breakthroughs are as follows:Firstly, the 1-d algorithm and 3-d algorithm tunnel air dynamics calculation methods is verified, and analysis is compare with theoretical calculation methods proposed by foreign scholars.Secondly, a calculation method put forward that is related with the micro-pressure wave at the long tunnel outlet. The micro-pressure wave problem at the long tunnel outlet could be solute by twice 3-d numerical calculation and a 1-d numerical calculation to obtain the final results. The method avoid the problem that computer hardware cannot satisfy requirements of all size 3d calculating, and solve 1-d calculation cannot simulate aerodynamic 3-d effect significantly section.Thirdly, the most unfavorable tunnel length range is determine in a 350km/h train, ballastless and ballast situation. In the ballast cases, with the tunnel length increases, The micro-pressure wave slow down gradually; When the tunnel length reach 6～8km, The micro-pressure wave reach maxium; After that, with the increase of tunnel length. The micro-pressure wave become smaller. In the ballastless cases, with the tunnel length increases,the pressure peak decreases.Lastly, compare and select hood form. Enlarging section and holed structure effectively lower the aerodynamics effects in numerical calculation, which is the best one in these several schemes.