Full-Scale Measurement and Numerical Simulation of Flow Around High-Speed Train in Tunnel

Abstract

Vibration of high-speed trains increases in tunnels caused by aerodynamic force whose mechanism is unknown. To investigate this aerodynamic force, the authors conduct an analysis of the running test data and a numerical simulation. The running test data indicates that the aerodynamic force acts to vibrate the train in the tunnel and it originates from large-scale coherent structures in the space between the tunnel wall and the train. These flow structures develop from the head toward the 6th to 8th cars, and become steady thereafter to the tail of the train set. The computation reveals that the flow becomes unstable under the train. The resulted vortices are spread on the train side by the tunnel wall, and then the unsteady aerodynamic force arises when the vortices pass.

Measurement of Air Velocity and Pressure Distributions around High-Speed Trains on Board and on the Ground

“…Note that, from the previous results obtained in running experiments of several series of Shinkansen trains (5) , flow fields focused on here around the A and B-Series trains can be considered almost the same. The lengths of the trains are about 405 m and that of the tunnel about 3 km.…”

“…1 Layout of equipment on the window of the A-Series train tunnels. Later, the effect of aerodynamic forces acting on the sides of trains was investigated (3)- (5) . Air velocity and pressure fluctuations on the sides of a high-speed train were simultaneously measured both in the open and in tunnel sections and aerodynamic forces on the car were estimated from the pressure data.…”

“…In addition, it was also shown that these results are independent of the types of Shinkansen trains. Numerical simulations and wind tunnel experiments for the flow around a high-speed train traveling in a tunnel have been conducted (5) (6) . In addition, a theoretical approach for the study of the dynamics of trains and train-like articulated systems subjected to fluid dynamic forces has been conducted recently (7)- (9) .…”

Study on the Influence of Blocking Ratio on Slipstream in Tunnel

“…Chen Guang, Key Laboratory of Traffic Safety on Track, Ministry of Education, School of Traffic & Transportation Engineering, Central South University, Changsha 410075, Hunan, China Velocity, pressure variation and direction of the flow inside tunnels are different than those around a train in open air [11][12] [13] . These differences can be related to the cross section and the length of the tunnel.…”

Pressure Fluctuation Characteristics of Narrow Gauge Train Running Through Tunnel

“…As one of the factors causing the phenomenon, aerodynamic force has attracted attention. Full-scale measurements conducted on the various types of Shinkansen trains elucidated characteristics of the aerodynamic force as follows (2) : (1) Continuous pressure fluctuation, which mainly causes the unsteady aerodynamic force, emerges on the side of train facing the tunnel wall. (2) The magnitude of the pressure fluctuation increases proportionately to the square of the airspeed relative to the train.…”