Numerical Analysis of the Effect of Different Nose Shapes on Train Aerodynamic Performance

Abstract

This study investigates the aerodynamic performance of various trains with different nose shapes, using as the design variables two angles (Formula presented.) for the head shape and the bluntness angle (Formula presented.), without crosswind. The effects on aerodynamic performance, such as the train drag coefficient, pressure distribution along the train surface, flow structures around the train and the wake, and head pressure pulse, are analyzed. The results indicate that the increase in the train nose length for flat shapes decreases the (Formula presented.) values by (Formula presented.) and (Formula presented.), decreasing the high-pressure region in the leading head. The duck nose configuration emerges as a compromise between drag reduction and nose length. Increasing the angle (Formula presented.), a further drag reduction of (Formula presented.) is featured. Drag formation along the train is also analyzed. The steeper the variation in the geometry, the higher the peak intensity and the slope of the curve. Regarding the flow features around the train, two main counter-rotating vortices are captured in the wake. Moreover, the higher the nose length and the higher the bluntness angle (Formula presented.), the weaker and narrower the wake. Again, a longer nose shape yields a softer jump in terms of pressure difference, crucial for train homologation and safety.