A study on reducing aerodynamic drag of trains by smoothing the under-floor surface

Abstract

As a train runs at higher speeds, the aerodynamic drag increases. On long train-sets such as those of Shinkansen, the aerodynamic drag is mainly generated by intermediate vehicles. In previous researches, we proved that smoothing the under-floor surface reduces the aerodynamic drag. To investigate the mechanism of this effect, we performed wind tunnel tests with train models consisted of three vehicles, each representing a head, intermediate and tail vehicle, and measured the aerodynamic drag and pressure distributions on the intermediate vehicle. We divided the aerodynamic drag of the intermediate vehicle into the components at different parts of the carbody and clarified the effect of smoothing the under-floor surface to decrease the aerodynamic drag.