Three-Dimensional Numerical Simulation Of Aerodynamic Effect Produced By High-Speed Train Entering A Tunnel

Owing to the compressibility of air and the limited flowing space, when the train entersthe tunnel with high-speed, there will be initial compression waves, pressure waves in tunneland entry waves induced inside or outside the tunnel. And, because of the asymmetry of theflow around the train body, there will be lateral vibration problems appeared. With theincreasing of the speed of train, the tunnel aerodynamics will be paid more attention to theride comfort problem. Consequently, pressure waves in and out the tunnel are thephenomenon that are with great value to study.Constructing the aerodynamic model of high-speed train and the corresponding to thetunnel model to make the three-dimensional unsteady and compressible turbulent flow gridmodel is based on numerical simulation. Applying STAR-CD software in flow numericalsimulation based on finite volume method and Arbitrary Sliding Interface(ASI), we applyaerodynamic analysis related to the analysis to the characteristics of initial compression waves,pressure waves in tunnel, entry waves, train surface pressure wave, aerodynamic force andaerodynamic torque.It is valuable to make comparison with three different grid scales on thephenomenon mentioned above. Meanwhile, the numerical simulation results of the entrywave, pressure in tunnel and the pressure of measure points on the train body with highReynolds SST k ωturbulent model, RNG k εmodel and standard k εmodel arecompared. We conduct the mesh work included the ideas of partition and different densityareas to reduce mesh number and make sufficiently use of the computing resources.The result shows that the results of entry waves description tend to the most intensivemesh among three different mesh systems. Meanwhile, the initial compression waves givingout the waveform, stress nephogram and velocity vector diagram shows the attenuationcharacteristics of entry wave. Because of the asymmetry of the flow field, this induces thedifference of forces on two sides of the train which causes the lateral vibration problem. Thereis little difference among the results of entry wave and pressure wave in tunnel with highReynolds SST k ωturbulent model, RNG k εmodel and standard k εmodel. Butthere is much difference from the pressure on the head and tail.The three-dimensional numerical simulation can effectively shows the relation betweenthe pressure fluctuation inside or outside the tunnel and on the train. The result of this thesis isuseful to give some advice to the pressure fluctuation inside or outside the tunnel caused bythe unbalance of the force and moment which provide some useful reference for train safetyand stable movement.