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

Abstract

AbstractIn this paper are presented PIV measurements of turbulent pipe flow at bulk Reynolds numbers Re$$_D$$ D between 3.4$$\times$$ × 10$$^5$$ 5 and 6.9$$\times$$ × 10$$^5$$ 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$$_D$$ D = 4.98$$\times$$ × 10$$^5$$ 5 , corresponding to a shear Reynolds number Re$$_\tau$$ τ = 10.3$$\times$$ × 10$$^3$$ 3 , with a spatial resolution in wall units of $$\varDelta y^+$$ Δ y + = 19.