Effect of Freestream Turbulence and Flow Recovery in the Wake of a Flat Plate

The study of the recovery of an open channel boundary flow in the presence of increased freestream turbulence (FST) generated in the wake region of a surface mounted flat plate is presented. Detailed LDA velocity measurements were obtained upstream and downstream of the flat plate, which is 3 mm in thickness and has a thickness-to-chord ratio of 0.12. The chord is placed parallel to the flow direction. The characteristics of the mean velocity, turbulence intensity, and the velocity skewness and flatness factors were investigated. The skin friction was increased while the strength of the boundary layer wake parameter decreased in the wake region. The turbulence intensity profiles in the wake region increasingly deviated significantly from the upstream profile. Generally, the increased FST noticed in the near-wake region was observed to decay with downstream distance. As a result, the mean velocity and turbulence intensity profiles showed a general sense of recovery towards the state of the approaching flow.