2026-09-21T07:47:30Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/18274 2023-07-10 col_2142_5131 col_2142_14787 com_2142_5130 com_2142_9630 com_2142_234

Christensen, Kenneth T. Licari, Anthony M. 2011-01-14T22:43:33Z 2011-01-14T22:43:33Z 2011-01-14T22:43:33Z 2010-12 The present effort investigated the influence of cumulative damage of an initially smooth surface on the statistical characteristics of wall turbulence. Singular value decomposition was employed to decompose a highly-irregular surface topography replicated from a turbine blade damaged by spallation into topographical modes embodying successively smaller roughness length scales. These modes were then used to develop multiple reduced-order models of the original roughness that, at least in spirit, successively captured the evolution of the surface roughness from initial smaller-scale defects that would likely form just after deployment to the eventual cumulative formation of larger-scale roughness features. Particle-image velocimetry measurements of flow at a friction Reynolds number around 1825 over various topographical models were gathered in turbulent channel flow. The cumulative impact of these reduced-order models on wall turbulence was then assessed by comparing mean velocities, Reynolds normal stresses, and Reynolds shear stresses. It was observed that the turbulence statistics of the flow increase in magnitude as larger-scale features are introduced into the surface, leading up to the full, original surface. In addition, even weak surface damage that a practical flow surface might endure within the first fraction of its deployment lifetime can significantly enhance turbulence and therefore progressively degrade system performance. Thus, proper modeling of flow-system performance must account for the dynamic nature of flow surfaces, particularly those exposed to severe operating conditions. Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2010-12-06T22:15:01Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 8 thesisbib.bib: 18531 bytes, checksum: a1d652993e21c36194a48f7f8bb0735f (MD5) thesis.tex: 6404 bytes, checksum: a3ecbda82a041045e67c8c40a7eb1b17 (MD5) structure.tex: 38960 bytes, checksum: 7415648babae2a1062cf7e33e87aa902 (MD5) results.tex: 55729 bytes, checksum: 6455781927a853d2280dc110994a88bb (MD5) experiment.tex: 47781 bytes, checksum: f8c07e566946f77d5a24ba6c48a449c3 (MD5) conclusions.tex: 5997 bytes, checksum: dcbdd6b78252f140ff6703c734524406 (MD5) appendix.tex: 17522 bytes, checksum: 657d24b51de76fb63b5fa80771ff5b87 (MD5) Licari_Anthony.pdf: 12941887 bytes, checksum: 1d721aaa90bc80bc7ca7d1416e090f4b (MD5) Made available in DSpace on 2011-01-14T22:43:33Z (GMT). No. of bitstreams: 9 Licari_Anthony.pdf: 12941887 bytes, checksum: 1d721aaa90bc80bc7ca7d1416e090f4b (MD5) appendix.tex: 17522 bytes, checksum: 657d24b51de76fb63b5fa80771ff5b87 (MD5) conclusions.tex: 5997 bytes, checksum: dcbdd6b78252f140ff6703c734524406 (MD5) experiment.tex: 47781 bytes, checksum: f8c07e566946f77d5a24ba6c48a449c3 (MD5) results.tex: 55729 bytes, checksum: 6455781927a853d2280dc110994a88bb (MD5) structure.tex: 38960 bytes, checksum: 7415648babae2a1062cf7e33e87aa902 (MD5) thesis.tex: 6404 bytes, checksum: a3ecbda82a041045e67c8c40a7eb1b17 (MD5) thesisbib.bib: 18531 bytes, checksum: a1d652993e21c36194a48f7f8bb0735f (MD5) license.txt: 4063 bytes, checksum: 9b76f8728a77bcc2f25e97a62c0212ff (MD5) http://hdl.handle.net/2142/18274 en Copyright 2010 Anthony M. Licari turbulence channel flow Particle image velocimetry (PIV) surface roughness cumulative damage Modeling Cumulative Damage to Flow Surfaces and Assessing its Impact on Wall Turbulence Mechanical Sci & Engineering 1917 Mechanical Engineering 0133 University of Illinois at Urbana-Champaign Thesis M.S. MS:Mechanical Engineerng -UIUC 10KS0133MS