Quantification of the Aerodynamic Gain on Two Virtually Coupled Modular Trains

To make railway systems more autonomous and energy efficient, the suction phenomenon induced by virtual coupling (VC) can be considered as a beneficial source of energy saving since trains are very closely spaced. A minimum safe distance between railway systems must be defined and maintained to ensure the safety of the whole convoy. The purpose of this paper is to study and quantify the aerodynamic gain in case of VC of two modular and autonomous trains ‘Smart Cabins’ as designated in our project. Computational fluid dynamics simulations are investigated to analyze the aerodynamic effect under several scenarios by varying the inter-cabins distance. Some design simplifications have been made for each Smart Cabin to prepare simulations and reduce computation time. Simulation results confirm the interest of VC in the sense of reducing coefficient drag of the full convoy up to 27%, which reflects a power gain of about 4% of the total traction power required for a single Smart Cabin (~200 kW).