Experimental study on the effect of Reynolds number on aerodynamic performance of high-speed train with and without yaw angle

The influence of the Reynolds number on the aerodynamic force and pressure of a train was investigated experimentally at yaw angles of 0° and 15°. Two kinds trains were scaled at 1:8 and 1:20, respectively, and the Reynolds number, based on the train height, ranged from 3.02×105 to 2.27×106. The pressure distribution along a train at yaw angles of 0° and 15° was researched, and the results are compared herein. The difference in Reynolds number effect between the head and tail cars is also discussed. The results show that the lift coefficient of a train increases with an increase in Reynolds number at a yaw angle of 15°, and the other force coefficients decrease with an increase in Reynolds number. There are significant differences between the positive and negative pressures in terms of the Reynolds number effect. The yaw angle weakens the Reynolds number effect on the pressure coefficient on the head car, whereas the influence of the yaw angle on the Reynolds number effect on the pressure coefficient for the tail car is relatively complex.