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Title:Iced Airfoil Separation Bubble Measurements by Particle Image Velocimetry
Author(s):Jacobs, Jason J.
Doctoral Committee Chair(s):Bragg, Michael B.
Department / Program:Aerospace Engineering
Discipline:Aerospace Engineering
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Engineering, Aerospace
Abstract:Previous iced airfoil investigations have demonstrated somewhat reduced aerodynamic penalties resulting from a three-dimensional ice simulation, compared to those of a two-dimensional ice simulation of a representative cross section. Correspondingly, the current measurements revealed accelerated transition of the separated shear layer emanating from a three-dimensional ice simulation and therefore enhanced pressure recovery and reduced mean separation bubble length, each relative to the flowfield of a representative two-dimensional ice simulation. These effects appeared to result from the quasi-steady distribution of discrete, streamwise vortices which aided the turbulent entrainment of fluid from the recirculation region of the three-dimensional ice simulation separation bubble flowfield. These vortices were generated by a streamwise-vortex instability excited by roughness along the three-dimensional ice simulation and produced spanwise-cell structures throughout this flowfield, as well as significant spanwise variation in peak turbulence statistics. However, these variations were strongly correlated to the local degree of flowfield three-dimensionality observed from surface oil-flow visualization, indicating a three-dimensional relieving effect, such that measurements within a quasi-two-dimensional spanwise region were both qualitatively and quantitatively similar to those of the two-dimensional ice simulation separation bubble flowfield.
Issue Date:2007
Description:416 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007.
Other Identifier(s):(MiAaPQ)AAI3290256
Date Available in IDEALS:2015-09-25
Date Deposited:2007

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