明り区間とトンネル区間における列車中間部の空気抵抗の評価

抄録

Scale model launching experiments and numerical calculations were carried out to evaluate the aerodynamic drag of the middle part of a train in the open air and in tunnels. Scale model launching experiments were performed by projecting two types of cylindrical trains with smooth and concave-convex surfaces into three types of circular tube tunnels with different diameters to measure pressure variations in the tunnels. Friction factors of the middle part of the trains in the tunnels were determined by comparing pressure variations of the numerical calculations to those of the experiments. Friction factors in the open air were estimated from the factors in the tunnels by extrapolation method in certain conditions. Based on the obtained friction factors, it is demonstrated that the aerodynamic drag of a Shinkansen train estimated from the friction factors in the tunnels is approximately 4 to 8 percent greater than that in the open air.