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oai:www.ideals.illinois.edu:2142/87693 2023-07-11 col_2142_5131 col_2142_46414 com_2142_5130 com_2142_178 com_2142_234

Adrian, Ronald J. Christensen, Kenneth Thor 2015-09-28T16:23:27Z 2015-09-28T16:23:27Z 10000-01-01 2001 2001 The velocity time derivatives are associated predominantly with small scales in both space and time. Examination of instantaneous and estimates of the conditionally averaged velocity time-derivative fields indicates that the smaller-scale vortices leave a convective imprint upon the time derivatives. Further, the streamwise spectra of the velocity time-derivative support the notion that convective effects dominate the smaller scales of the flow. Comparison between the bulk convective-derivative and time-derivative spectra illustrate this behavior. At low wavenumbers, the bulk convective-derivative and time-derivative spectra coincide with one another, implying that the larger scales are dominated by evolution. At moderate wavenumbers (coincident with the streamwise spacing of the vortices associated with the outer-layer vortex organization noted earlier), the energy associated with convection reaches a maximum. With increasing Reynolds number, the influence of convective effects diminishes at all wavenumbers in terms of its contribution to the energy of the velocity time derivative. This behavior is quite encouraging from the LES-modeling viewpoint, where capturing the true evolution of the flow is the main goal. Made available in DSpace on 2015-09-28T16:23:27Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 3017051.pdf: 11753337 bytes, checksum: d870b467bd412dcc55b1eaf00693959c (MD5) Previous issue date: 2001 Embargo set by: Seth Robbins for item 88974 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs U of I Only 239 p. Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2001. http://hdl.handle.net/2142/87693 (MiAaPQ)AAI3017051 eng Engineering, Mechanical Experimental Investigation of Acceleration and Velocity Fields in Turbulent Channel Flow text Theoretical and Applied Mechanics Theoretical and Applied Mechanics University of Illinois at Urbana-Champaign Dissertation Ph.D.