Experimental Study on the Unsteady Wake of a High-speed Train

Abstract

The unsteady wake of a 1/50 scale high-speed train (HST) is investigated experimentally in a wind tunnel. Based on hot-wire anemometry and Particle Image Velocimetry (PIV) measurement, it can be observed that the wake of a slender HST is dominated by a pair of counter-rotating streamwise trailing vortices and periodical anti-symmetric vortex shedding; Each of the streamwise trailing vortices presents increase/decrease alternately in size and vorticity, along with spanwise and vertical oscillation, which could be attributed to vortex shedding shed from the sides of the tail train. In addition, the interaction between trailing vortices and the ground induces second vortices and intensifies the unsteady features in the wake.