Abstract
Air velocity and pressure distributions on the sides of 16-car high-speed trains both in open and tunnel sections are measured to investigate the flow structure around the trains, especially in tunnels. For on-board measurement, hot-film probes, pitot tube rakes and pressure gauges are fixed on both sides of the 3rd car from the head end of the outbound train (and the 14th of the inbound). Two glass windows of the 3rd car are replaced with iron plates equipped with the apparatus. For on-the-ground measurement, ultrasonic anemometers and a pressure gauge are installed inside a tunnel at a point 800 m from a tunnel portal. The cruising speeds of the trains are set at between 250 and 290 km/h. It was found that the air velocity in the narrower space between the train side and the tunnel wall in the train coordinate system gradually decreases from the head toward the tail of the train while that in the other wider space increases, and that the features of the velocity and pressure fields observed on board in tunnel sections can be also detected on the ground.
