Aerodynamic analysis of trains with different streamlined lengths of heads

Aerodynamic analysis of trains in open air without crosswind was studied using the detached-eddy simulation (DES) method in the present work. Three kinds of train model, with different streamlined lengths of heads but the identical cross section and train length, were investigated. The streamlined lengths are 5m, 9m, and 15m, respectively. To find the influence of streamlined lengths on the aerodynamic properties, the drag coefficient, surface pressure, trackside pressure, slipstream velocity variation along the length of the train and the flow structures around the train, were compared and analyzed. The result of the total drag coefficient decreased 22.4% with the streamlined length increased from 5m to 15m. The longer streamlined length can reduce the strength of vortex shedding and wake flow effectively, and a minor positive pressure area was generated in the nose cone compared to shorter streamlined length.