Investigation of turbulence structure in recovery region of downstream flow over a forward-facing step with hot wire and PIV measurements

Abstract

Turbulence structures in recovery region of downstream flow over a forward-facing step are studied in Poiseuille and Couette flows. Large scale turbulence vortices are intermittently released from reattachment point of separation. Spectral analysis is carried out for velocity sequence obtained with hot wire velocimetry, and then pre-multiplied spectra is estimated in the downstream recovery region. Large scale turbulence vortices in the Couette flow are convected upward to the opposite wall, while the vortices in the Poiseuille flow are weakened due to the counter-rotating vortices developed near the opposite wall.