Structure of Turbulent Boundary Layers and Surface Pressure Fluctuations with Sparse Roughness

Nathaniel Varano, Roger Simpson
2010 48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition   unpublished
Measurements of the mean flow and turbulent statistics were made in a 2D flat plate turbulent boundary layer over several fetches of hemispherical roughness elements with various spacings using Laser Doppler Velocimetry (LDV). These measurements were used to study the effect of roughness spacing on the wall shear stress. Methods for estimating the wall shear stress by fitting data to a model profile were evaluated against an integral momentum balance technique. Results suggest that the von
more » ... t that the von Kármán constant may not be a constant for rough walls. Spectra of surface pressure fluctuations were also measured.
doi:10.2514/6.2010-700 fatcat:tbsi4z3inza67algpdimg4tdxq