Investigation of Turbulent Separation in a Forward-Facing Step Flow

D. S. Pearson, P. J. Goulart and B. Ganapthisubramani

in 13th European Turbulence Conference, Warsaw, Poland, September 2011.
BibTeX  URL 

  author = {D. S. Pearson and P. J. Goulart and B. Ganapthisubramani},
  title = {Investigation of Turbulent Separation in a Forward-Facing Step Flow},
  booktitle = {13th European Turbulence Conference},
  year = {2011},
  url = {},
  doi = {10.1088/1742-6596/318/2/022031}

The relation between the upstream and downstream regions of separation of the flow over a forward-facing step is investigated using experimental data. High-speed Particle Image Velocimetry (PIV) data is used to show a correlation between the wall shear stress of the oncoming boundary layer and the streamwise location of reverse flow upstream of the step. The time delay associated with the correlation is consistent with average convection velocities in the lower boundary layer. This suggests that appropriate addition of momentum into the boundary layer could be used to control the spatial extent of the separation upstream of the step. In addition, low-speed PIV data is used to show statistical relations between the flow characteristics of the recirculation regions in the vicinity of the step face. It is shown that a slower than average flow velocity above the step face is associated with an increase in the wall-normal extent of upstream reverse flow, an increase in the inclination of the flow above the step and an increase in downstream vorticity.