Flow control technique to modify the aeroacoustic andaerodynamic characteristics of a high-speed pantographby ejection of jets

摘要

Aeroacoustic and aerodynamic characteristics are very important for the pantographs of high speed train to ensure environmental compatibility and maintain steady current collecting performance. In general, these characteristics depend on a number of parameters, such as the attackangle, dynamic behavior of the pantograph, track conditions (open air or tunnel), and the wear of contact strips that determines pantograph configuration. Hence it is not easy to improve these two characteristics by improving only the shape of the pantograph. In this study, we attempt to modify itsaerodynamic and aeroacoustic characteristics by applying jets ejected from the surface of a panhead, which is comprised of the contact strips and their mounting. The holes from which jets are ejected, are opened in rows near the trailing edge of the panhead. This method has an advantage to be able to copewith different conditions as required. To estimate the effect of the jet ejection, the authors performed a wind tunnel test using a 2-dimensional panhead model equipped with a jet ejection device. The experimental results show that the pressure distribution on the model can be changed by adjusting the velocity of ejected jets. This means that the lift force can be controlled by the jet ejection. Furthermore, the conspicuous aeroacoustic noise generated by vortex street in the wake of the panhead can be reduced by the jet ejection. Therefore, this method has great potential for practical applications.