An attempt is made to measure wake-affected boundary layers on a flat plate by means of a split-film probe. Although a number of studies have been made to reveal the transitional behavior of boundary layers subjected to periodic wake passing, much is still unknown on the turbulence structure of those boundary layers. It is because most of the studies measured the boundary layers by single hot-wire probe. This measurement therefore aims at the determination of the turbulent structure of the incoming wakes as well as the disturbed boundary layers mainly in terms of ensemble-averaged Reynolds shear stress and turbulence intensity. Unsteady velocity vectors associated with the wakes and wake-induced turbulence patch (a number of turbulent spots) are also determined in detail. In comparison to a conventional how-wire probe, the probe used in this study is less sensitive to fluctuations of high frequency and less accurate in the near-wall measurement due to its relatively large diameter of its sensor. However, new and important information is obtained on the structure of wake-induced turbulence patch, which provides more insight into the wake-induced boundary layer transition than before. In addition, the measured velocity field following the turbulent patch indicates a clear image of calmed region.
Sensitivity of turbulent stresses in boundary layers to cross-wire probe uncertainties in the geometry and calibration procedure
