Wind tunnel experiment on aerodynamic characteristic of streamline head of high speed train with different head shapes

Wind tunnel experiments of four different longitudinal slenderness ratio high-speed trains including CRH2 were carried out to analyze the influence of Reynolds number on train aerodynamic force coefficients,with the scale of all models used being 1:8.The aerodynamics character of these four trains were compared and wind tunnel experiments were conducted with big side slip angle to research on the high-speed train safety under strong cross-wind.The results show that the aerodynamic drag can be reduced with the much longer streamlined head,more sharp nose and smoother streamlined head.Besides,when longitudinal slenderness ratio coefficient is lager,the head of train is longer and slender,it is the more favorable for the drag reduction when the difference among the length of train models is not much.As the side slip angle increases,the side force coefficient and lift coefficient of head car,middle car and tail car increase.When the side slip angle is greater than 10°,the side force of the train with the bigger maximum longitudinal profile curvature under cross-wind is significantly larger than those of the other three projects,while the lift coefficient is smaller.