Numerical Study On Unsteady Aerodynamic Characteristics Of High-speed Train And Tunnel System

The pressure waves formed from high-speed train moving into the tunnel affect the safety and satisfaction of the passengers; Micro-pressure waves around the tunnel exit cause tremendous explosion sound; With the increase of train speed, the drag increase hugely, inducing energy waste. The aerodynamics of high-speed train in tunnel has become an important issue.The pressure waves and the air drag and micro-pressures of train are studied by computation of the compressible Navier-Stockes equations and κ-ε equations. The results show that:The initial compression wave’s peak is proportional to the square of speed. The maximum value of pressure wave gradient is proportional to the cube of speed. The aerodynamics drag is a power proportional to the velocity of train, and its frequency is greater than2. When the block is large, the blockage has a great impact on the aerodynamics drag. When the blockage is relatively small, the blockage has little influence on the aerodynamics drag. Train’s length has little effect on the pressure drag, but it’s proportional to the fraction drag. The micro-pressure’s peak is proportional to the cube of speed and is proportional to blockage. Meanwhile the micro-pressure’s peak is inversely proportional to the distance from the exit of tunnel. With the increase of the shaft’s number and the shaft’s area, the micro-pressure’s peak decreases.