Experimental characterization of the near-wall turbulence in rough supercritical flows

Abstract

Turbulence is a fundamental phenomenon in fluid mechanics and plays an important role in many fluvial processes. The key objective of this paper is the experimental characterization of the near-wall turbulence in supercritical open-channel flows. The work explores a laboratorial database of twocomponent instantaneous velocity series, collected in the vicinity of the bed, by means of Laser Doppler Anemometry. Different flow conditions were analyzed, with Reynolds number ranging from 10(4) to 4 x 10(4) and Froude numbers between 1.3 and 1.8. Turbulent flow variables were measured in order to analyze the behavior of the flow near the wall. The obtained data for the different flow conditions allowed for the quantification of turbulence through statistical moments, spectra and second and third-order structure functions. A comparison between the obtained and the literature values was also performed and discussed.