2026-09-18T19:34:19Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/22703 2023-07-10 col_2142_5131 col_2142_14787 com_2142_5130 com_2142_9630 com_2142_234

Dutton, J. Craig Messersmith, Nathan Lee 2011-05-07T13:48:39Z 2011-05-07T13:48:39Z 10000-01-01 1992 The large scale structure and scalar transport characteristics of compressible turbulent mixing layers have been experimentally investigated at various levels of compressibility in order to study the fundamental effects of compressibility on the nature of the mixing layer. Nonintrusive optical diagnostic techniques were employed to image the large structures. Both Mie scattering from condensed ethanol droplets and laser-induced fluorescence from seeded nitric oxide were used. The LIF experiments were utilized to avoid potential particle dynamics effects associated with the Mie scattering experiments. Sizeable ensembles of digital images were collected for a variety of seeding styles, image planes and at three distinct flow conditions. Analysis of the samples provided mean and standard deviation profiles, two-dimensional spatial covariance fields and passive scalar probability density functions. In the transverse image plane, the dimensionless structure size and eccentricity increased, while the angular orientation of the structures with respect to the streamwise flow direction decreased, as the relative Mach number increased. Oblique views revealed significant three-dimensionality, and the structures imaged in this view also increased in dimensionless size with compressibility. Very little difference in the total probabilities of finding mixed fluid within the shear layer was found for flows with relative Mach numbers of 0.63 and 1.49. A relative Mach number 0.98 flow, however, demonstrated substantially lower mixed fluid probabilities, concomitant with a very high peak standard deviation. Instability mode interactions may be the cause of the disturbed nature of the mixing layer at this condition. The results from the Mie scattering and laser-induced fluorescence experiments for similar shear layer conditions were very comparable. Made available in DSpace on 2011-05-07T13:48:39Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9215855.pdf: 11367739 bytes, checksum: b213f8ab8213d0500e5ee3f7ebd3fb85 (MD5) Previous issue date: 1992 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:59:25Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:28:02-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission ETDs are only available to UIUC Users without author permission U of I Only AAI9215855 (UMI)AAI9215855 http://hdl.handle.net/2142/22703 eng Copyright 1992 Messersmith, Nathan Lee Engineering, Aerospace Engineering, Mechanical An experimental investigation of organized structure and mixing in compressible turbulent free shear layers text Mechanical Science and Engineering Mechanical Science and Engineering University of Illinois at Urbana-Champaign Dissertation Ph.D.