The pressure waves of a high-speed train in a tunnel exhibit complicated variations in their characteristics because the waves propagate and reflect with superposition. Studies have been consistently carried out on the pressure waves of a single train since changes in the area of pressure is a key element that influences ride comfort. Recently, the frequency of the operation of coupled trains has increased in order to improve the efficiency of running a train. The cross-sectional area of a train entering a tunnel has a rate of change that greatly influences the pressure characteristics; therefore, a coupled train can have different pressure characteristics when compared to a single train. However, adequate research works have not been done to assess these characteristics. To this end, the pressure characteristics of a train according to the operating conditions are investigated in this study. A high-speed train operating in practice and a tunnel located in a service section were chosen for this study, and the pressure characteristics of a single train were assessed via numerical analysis and an experiment. The numerical analysis was carried out with high reliability by comparing and verifying each result. After the pressure wave characteristics caused by running a coupled train had been assessed by the established numerical analysis, an obvious pressure variation was confirmed to occur at the connecting point. In addition, the maximum pressure applied to a tunnel and a passenger car increased. Thus, the aerodynamic effect of a coupled train should be considered as an important parameter in the early design state of a new high-speed train.
Experimental Study on Pressure Wave Characteristics of High-Voltage Discharge in Water with Hemispherical Electrodes
