Experimental investigation on the turbulent separated and reattaching flow over backward-facing step

Two-dimensional separated and reattaching turbulent flow over a backwark-facing step in a low-speed water channel was extensively investigated using Particle Image Velocimetry (PIV). Time-averaging reattaching position, velocity field and spanwise vorticity field were revealed. Turbulence intensity field and Reynolds stress field were delineated using statistical analysis based on a large number of measured velocity vector felds. Flow characteristics involved in amalgamations of small vertices and formation of large-scale coherent structures were disclosed.