View article

The structure of inner-outer interactions in a smooth-wall turbulent boundary layer is investigated using high-frame-rate particle image velocimetry (PIV) with two overlapping fields of view. A refractive-index-matched facility is used to enable the resolution of turbulent structures very close to the wall where these modulation effects are dominant. Amplitude and frequency modulation correlation coefficients were first investigated by computing single-, two-, and multiple-point correlation analyses now routinely reported in the literature. The wall-normal trends in amplitude modulation for the streamwise and wall-normal velocities and in frequency modulation for the streamwise velocity are consistent with those previously reported in the literature, validating the efficacy of the PIV approach used herein. The frequency modulation behavior for wall-normal velocity, however whose behavior in this regard has received little …