Conditional averages of large scale motions through synchronous PIV and surface shear stress measurements – Proceedings of the 13th International Symposium on Particle Image Velocimetry Jul 2019

Synchronous stereo particle image velocimetry (PIV) and fluctuating wall shear stress measurements were performed in a moderate Reynolds number zero pressure gradient turbulent boundary layer. Multiple, discrete PIV planes allow for a reconstruction of the wall shear stress-streamwise velocity cross correlation in a volume around the sensor. The velocity field is averaged on imposed conditions of the wall shear stress to identify large scale motions during these conditions. A simple condition based on large scale dynamics is introduced to identify periodic patterns of the velocity field associated with wall-distance scaling. This study represents a novel application of microelectromechanical systems floating element wall shear stress sensor types simultaneously with PIV, and addresses experimental procedures to prevent degradation and signal corruption caused by both seeded flow and laser radiation.

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