Experimental investigation of the near and far field structure of high Reynolds number turbulent boundary layers

A multiple camera, multiple resolution PIV system is used to capture a large streamwise, wall-normal field of view (2δ × 1.5δ), while simultaneously resolving the near-wall flow down to a height of y⁺ ≈ 3 at Reynolds numbers of Reτ ≈ 8,000 to 20,000. The high spatial resolution in the near-wall vicinity is used to provide a direct estimate of the wall shear stress and subsequent analysis of both the small near-wall and larger outer flow structure conditional on the local friction velocity and conversely on larger scale fluctuations. Conditional two-point correlations, and conditional mean structures will be presented.