THE IMPORTANCE OF AERODYNAMICS IN THE DESIGN OF INTRA-URBAN TRAINS TRAVELLING IN TUNNELS

Aerodynamics can be a major factor in the design and operation of intraurban subway-train transportation systems. In order to develop an adequate understanding of the aerodynamic characteristics of such systems, an experimental program was carried out. The major portion of the testing was conducted under equilibrium, incompressible conditions so that the fundamental aerodynamic characteristics could be isolated. The effects of geometric parameters (such as train speed, blockage ratio, wall roughness, and train speed, blockage ratio, wall roughness, and train and tunnel length) upon train drag and tunnel flow velocities were determined and compared with a simple theoretical model. The effect of aerodynamic forces upon typical subway-train operations is shown in order to give proper perspective to the importance of aerodynamics.