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oai:www.ideals.illinois.edu:2142/97778 2023-07-11 col_2142_5131 col_2142_14800 com_2142_5130 com_2142_14799 com_2142_234

Dutton, J. Craig Elliott, Gregory S. Favale, James V 2017-08-10T20:33:23Z 2017-08-10T20:33:23Z 2019-08-11T09:15:35Z 2017-04-25 2017-05 The supersonic flow separating past a cylindrical afterbody generates a complex, compressible and highly turbulent flowfield. This flow models several realistic applications, such as the wake region behind projectiles, bullets and unpowered rockets. A blowdown-type supersonic wind tunnel built specifically for axisymmetric base flows, located at the University of Illinois at Urbana-Champaign, is used to investigate these base flows. The flow is studied here via non-time-correlated instantaneous velocity vector fields obtained using stereo particle image velocimetry (S-PIV). Two overlapping velocity vector fields are simultaneously acquired and stitched together to obtain a high-resolution velocity vector field of the full flow. Statistics derived from the measurements, including the mean velocities and turbulence statistics (such as the kinematic Reynolds stresses), are presented in order to study the overall flow organization and turbulence levels. The obtained data are also used to provide benchmark data for CFD simulation comparison. The in-plane velocity component data are validated against LDV and planar PIV data obtained previously in the same facility. In order to gain further insight into the global organization of the flow, proper orthogonal decomposition (POD) is performed. The energy convergence and the structures found in the eigenmodes are used to gain insight into the organization of the flow that may not be apparent by observation of the mean flow statistics or the instantaneous images. The resulting eigenmodes of the POD analysis indicate that there is a dominant global axial pulsing motion. Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2019-05-01 The student, James Favale, accepted the attached license on 2017-04-25 at 11:50. The student, James Favale, submitted this Thesis for approval on 2017-04-25 at 11:55. This Thesis was approved for publication on 2017-04-25 at 18:07. DSpace SAF Submission Ingestion Package generated from Vireo submission #11039 on 2017-08-10 at 15:06:57 Made available in DSpace on 2017-08-10T20:33:23Z (GMT). No. of bitstreams: 2 FAVALE-THESIS-2017.pdf: 4727816 bytes, checksum: 801a1e1daeccd2066b84af5e750e50cf (MD5) LICENSE.txt: 4209 bytes, checksum: 6cad0bd8243469958617387c2458965d (MD5) Previous issue date: 2017-04-25 Embargo set by: Colleen Fallaw for item 102831 Lift date: 2019-08-10T21:27:21Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system U of I Only Restriction Lifted for Item 102831 on 2019-08-11T09:15:35Z. application/pdf http://hdl.handle.net/2142/97778 en Copyright 2017 James Favale Supersonic Base flow Particle image velocimetry (PIV) Stereoscopic PIV measurements and proper orthogonal decomposition of a supersonic axisymmetric base flow text text Aerospace Engineering Aerospace Engineering University of Illinois at Urbana-Champaign Thesis M.S.