Basic Research by Numerical Simulation on Mechanism of Aerodynamic Noise Generation

Shinkansen aerodynamic noise increases in proportion to the sixth to eighth power of train running speed, making it one of the biggest issues in increasing train speed. In efforts to tackle that issue, the authors carried out large-scale numerical simulation using the Earth Simulator supercomputer system on gaps between cars and for pantographs, typical aerodynamic noise sources of Shinkansen trains. The simulation results revealed the mechanism of broadband aerodynamic noise generation at gaps between Shinkansen cars, proving that a series of measures to develop low-noise shapes based on the noise generation principle would be effective. Furthermore, numerical simulation of the whole pantograph with more complex shape clarified that part of the pantograph noise is caused by the interaction of aerodynamic flows between the intermediate hinge cover and the arm and between the pantograph head and the top hinge cover.