Measurement of high-Re turbulent pipe flow using single-pixel PIV

In this paper are presented PIV measurements of turbulent pipe flow at bulk Reynolds numbers Re D between 3.4 × 10 5 and 6.9 × 10 5 . So-called single-pixel correlation is applied that yields a superior spatial resolution that is slightly larger than the equivalent size of a pixel in the flow. The location and shape of the averaged correlation peak give the mean velocity and normal and Reynolds stresses. A novel aspect of the single-pixel correlation approach is the extension to determine the 2-point spatial correlation of the velocity fluctuations and the spectrum of the longitudinal velocity fluctuations. Detailed results are presented for Re D = 4.98 × 10 5 , corresponding to a shear Reynolds number Re τ = 10.3 × 10 3 , with a spatial resolution in wall units of Δ y + = 19.