Scaling of the wall-normal turbulence component in high-Reynolds-number pipe flow

Streamwise and wall-normal turbulence components are obtained in fully developed turbulent pipe over a Reynolds number range from 1.1 × 10⁵ to 9.8 × 10⁶. The stream-wise intensity data are consistent with previous measurements in the same facility. For the wall-normal turbulence intensity, a constant region in v'_r.m.s. is found for the region 200 ≤ y⁺ ≤ 0.1R⁺ for Reynolds numbers up to 1.0 × 10⁶. An increase in v'_r.m.s. is observed below about y⁺ ∼ 100, although additional measurements will be required to establish its generality. The wall-normal spectra collapse in the energy-containing region with inner scaling, but for the low-wavenumber region a y/R dependence is observed, which also indicates a continuing influence from the outer flow on the near-wall motions.