Numerical investigation on the aerodynamic resistances of double-unit trains with different gap lengths

Double-unit trains increase passenger capacity but also energy consumption. Therefore, research about the aerodynamic resistance of a double-unit train is great importance to save energy. In this study, commercial long-marshalling high-speed and 8 kinds are used investigate effect gap length on resistance. The results show that 8.5%-12.9% larger than train. It tail car (CC1 car) first single-unit head (CC2 second lead difference in For with different length, increases incrementally which mainly caused by CC1 CC2 cars. With (starting from 0 mm), cremental lengths. gradually when lengths become larger. mm slightly greater 25 mm.