Research on aerodynamic optimization of high-speed train's slipstream

Slipstream severely affects the safety of trackside workers and equipment. With use of profile superimposition method and vehicle modeling method, parametrization of the whole train is carried out. Then, a slipstream optimization study has been performed, taking components of slipstream in different directions at the standard heights, the drag coefficient of the whole train and the volume of the driving cab as the design objectives. For each design objective, one unique epsilon-TSVR surrogate model has been constructed. Six final Pareto sets have been obtained on the base of six groups of different fitness functions by using multi-objective particle swarm method. Results reveal that the volume of the driving cab keeps almost the same, compared to the original shape. The velocity components of train-induced wind at the positions 0.2 and 1.4 m above the top of the rail, and the drag coefficient of the train are reduced by 11.6%, 33.9%, 24.7%, 25.9% and 13.0% respectively. Sensitivity analysis reveals that the length of the streamline, the height of the train and the width of the train influence significantly on the aerodynamic performance, and the train with a tall and thin streamline will benefit in reducing the slipstream and aerodynamic drag.