Abstract
Relatively good quality isotropy is observed in the central region of a turbulent boundary layer developing over a mesh screen rough wall. Spectra of velocity and, more especially, vorticity fluctuations satisfy isotropy over a significant wavenumber range. Inertial range scaling exponents ζ u2 (p) and ζ u3 (p) of moments of order p(?8) of increments of the transverse velocity fluctuations u 2 and u 3 are significantly smaller than the exponents ζ u1 (p) of increments of the longitudinal velocity fluctuation u 1. Exponents inferred from the locally averaged values of squared transverse vorticity fluctuations are only slightly smaller than ζ u1 (p). The difference between ζ u1 (p) and ζ u2 (p) [or ζ u3 (p)] more likely reflects the departure from isotropy of inertial range scales. There is evidence to suggest that the difference decreases with an increase in the Reynolds number and/or a decrease in the magnitude of the mean shear.
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Received: 11 December 1997/Accepted: 8 April 1998
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Antonia, R., Shafi, H. Small scale intermittency in a rough wall turbulent boundary layer. Experiments in Fluids 26, 145–152 (1999). https://doi.org/10.1007/s003480050273
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DOI: https://doi.org/10.1007/s003480050273