Evolution of wall shear stress with Reynolds number in fully developed turbulent channel flow experiments
Abstract
The Reynolds-number-dependence of wall shear stress (τw) in fully developed, high-aspect-ratio turbulent channel flow is experimentally studied over the range of 230 ≤Reτ≤950 . The principal conclusion of the present work is that beyond Reτ∼600 , the wall shear stress evolves to an asymptotic state in which the statistical moments, probability density function, and power spectra of τw become independent of Reynolds number. In this state, the turbulent intensity, skewness and kurtosis of the wall shear stress take on values that are slightly larger than those previously measured, because prior estimates of these quantities did not resolve the full range of wall shear stress fluctuations, which extended beyond 10 standard deviations above the mean. For Reτ≳600 , the spectra of τw were found to collapse very well when using a wall-unit-based normalization, providing further evidence of an asymptotic state of the wall shear stress at large Reynolds numbers.
- Publication:
-
Physical Review Fluids
- Pub Date:
- July 2019
- DOI:
- 10.1103/PhysRevFluids.4.074606
- Bibcode:
- 2019PhRvF...4g4606G