Effect of roughness on the spatio-temporal characteristics of inner-outer interactions in a turbulent boundary layer

Gokul Pathikonda, Kenneth T. Christensen

Research output: Contribution to conferencePaperpeer-review

Abstract

Turbulent boundary layers over smooth and rough walls are investigated using high frame-rate PIV in a refractive-index-matched (RIM) flow facility to better understand the structure of inner-outer modulating interactions. The RIM enables well resolved investigation of the near-wall buffer and roughness sub- layers to identify the effect of large and very large scales on the same. A hexagonally-packed hemispherical roughness pattern is investigated, together with baseline measurements over a smooth wall. Amplitude and frequency modulation coefficients are computed for each case, and preliminary results have shown strong correlation coefficients over roughness compared to the smooth-wall baseline. The wall-normal velocity fluctuations in the roughness sub-layer are stronger compared to that in the smooth-wall near-wall region, and exhibit frequency modulation. The on-going work aims to investigate the effect of roughness geometry on this interaction structure using conditional averaging methods.

Original languageEnglish (US)
StatePublished - 2019
Externally publishedYes
Event11th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2019 - Southampton, United Kingdom
Duration: Jul 30 2019Aug 2 2019

Conference

Conference11th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2019
CountryUnited Kingdom
CitySouthampton
Period7/30/198/2/19

ASJC Scopus subject areas

  • Atmospheric Science
  • Aerospace Engineering

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