{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/22905"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/22905","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Large eddy simulations of bluff-body wakes on parallel computers","abstract":"The objective of the present research was to investigate the applicability of large-eddy simulations to predict the characteristics of turbulent wakes of bluff bodies. The problem considered concerns turbulent flow over a square cylinder placed normal to a uniform free stream. The Reynolds number selected for the simulations is 21,400 where detailed experimental data are available. The computation times required for such simulations are quite large because of the fine grids and the large number of time steps that are necessary. Therefore, these calculations have been performed on massively parallel processing computers. The governing equations are approximated by a finite-volume discretization. Several alternate interpolation schemes, including a third-order (QUICK), a fifth-order, and a seventh-order upwinding-biased scheme, have been employed for convection terms. A data-parallel algorithm has been developed on the CM-5 machine, and its performance has been evaluated on various grid sizes in model flow problems and for different partition sizes.","abstract_html":"The objective of the present research was to investigate the applicability of large-eddy simulations to predict the characteristics of turbulent wakes of bluff bodies. The problem considered concerns turbulent flow over a square cylinder placed normal to a uniform free stream. The Reynolds number selected for the simulations is 21,400 where detailed experimental data are available. The computation times required for such simulations are quite large because of the fine grids and the large number of time steps that are necessary. Therefore, these calculations have been performed on massively parallel processing computers. The governing equations are approximated by a finite-volume discretization. Several alternate interpolation schemes, including a third-order (QUICK), a fifth-order, and a seventh-order upwinding-biased scheme, have been employed for convection terms. A data-parallel algorithm has been developed on the CM-5 machine, and its performance has been evaluated on various grid sizes in model flow problems and for different partition sizes.","abstract_has_math":false,"creators":["Wang, Gang"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Mechanical Science and Engineering","degree_department":null,"school":null,"contributors":["Vanka, Surya Pratap"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-07T13:55:23Z","date_published":"2011-05-07T13:55:23Z","updated_at":"2026-07-22T22:25:20Z","subjects":["Engineering, Mechanical","Computer Science"],"languages":["eng"],"rights":["Copyright 1996 Wang, Gang"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["9780591199567","AAI9712474","(UMI)AAI9712474"],"render_values":[{"text":"9780591199567","href":null,"code":true},{"text":"AAI9712474","href":null,"code":true},{"text":"(UMI)AAI9712474","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/22905","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Vanka, Surya Pratap"]},{"key":"dc:creator","label":"Author","values":["Wang, Gang"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-07T13:55:23Z","10000-01-01","1996"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Mechanical Science and Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Engineering, Mechanical","Computer Science"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1996 Wang, Gang"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["9780591199567","AAI9712474","(UMI)AAI9712474","http://hdl.handle.net/2142/22905"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The objective of the present research was to investigate the applicability of large-eddy simulations to predict the characteristics of turbulent wakes of bluff bodies. The problem considered concerns turbulent flow over a square cylinder placed normal to a uniform free stream. The Reynolds number selected for the simulations is 21,400 where detailed experimental data are available. The computation times required for such simulations are quite large because of the fine grids and the large number of time steps that are necessary. Therefore, these calculations have been performed on massively parallel processing computers. The governing equations are approximated by a finite-volume discretization. Several alternate interpolation schemes, including a third-order (QUICK), a fifth-order, and a seventh-order upwinding-biased scheme, have been employed for convection terms. A data-parallel algorithm has been developed on the CM-5 machine, and its performance has been evaluated on various grid sizes in model flow problems and for different partition sizes.","For turbulent flow over a square cylinder, the turbulence evolves gradually with the downstream distance with varying energy spectra and small scale content. The dynamic sub-grid scale model can provide a good spatial distribution of the eddy viscosity as the computed Smagorinsky coefficient varies with time and space. Several calculations with progressive improvement in numerical accuracy and grid resolution have been conducted. The calculated integral parameters and time-averaged profiles of velocities and Reynolds stresses have been compared with the experimental data. Good agreement has been observed in several of the quantities compared, although further improvement is desirable. Further, we have presented some fundamental aspects of the large-scale flow characteristics. We have studied the low-frequency flapping phenomenon which is observed in the auto-correlations and the energy spectra of the fluctuating velocities. We have also presented two-dimensional and three-dimensional vortical structures, and the phase-averaged quantities which have been compared qualitatively with the experiments.","Made available in DSpace on 2011-05-07T13:55:23Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9712474.pdf: 6679842 bytes, checksum: 793b24b33be0a8cc73a5b88a075791db (MD5) Previous issue date: 1996","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T15:00:49Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:28:48-05:00 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"]},{"key":"dc:title","label":"Title","values":["Large eddy simulations of bluff-body wakes on parallel computers"]}]}],"canonical_facts":{"dc:contributor":["Vanka, Surya Pratap"],"dc:creator":["Wang, Gang"],"dc:date":["2011-05-07T13:55:23Z","10000-01-01","1996"],"dc:description":["The objective of the present research was to investigate the applicability of large-eddy simulations to predict the characteristics of turbulent wakes of bluff bodies. The problem considered concerns turbulent flow over a square cylinder placed normal to a uniform free stream. The Reynolds number selected for the simulations is 21,400 where detailed experimental data are available. The computation times required for such simulations are quite large because of the fine grids and the large number of time steps that are necessary. Therefore, these calculations have been performed on massively parallel processing computers. The governing equations are approximated by a finite-volume discretization. Several alternate interpolation schemes, including a third-order (QUICK), a fifth-order, and a seventh-order upwinding-biased scheme, have been employed for convection terms. A data-parallel algorithm has been developed on the CM-5 machine, and its performance has been evaluated on various grid sizes in model flow problems and for different partition sizes.","For turbulent flow over a square cylinder, the turbulence evolves gradually with the downstream distance with varying energy spectra and small scale content. The dynamic sub-grid scale model can provide a good spatial distribution of the eddy viscosity as the computed Smagorinsky coefficient varies with time and space. Several calculations with progressive improvement in numerical accuracy and grid resolution have been conducted. The calculated integral parameters and time-averaged profiles of velocities and Reynolds stresses have been compared with the experimental data. Good agreement has been observed in several of the quantities compared, although further improvement is desirable. Further, we have presented some fundamental aspects of the large-scale flow characteristics. We have studied the low-frequency flapping phenomenon which is observed in the auto-correlations and the energy spectra of the fluctuating velocities. We have also presented two-dimensional and three-dimensional vortical structures, and the phase-averaged quantities which have been compared qualitatively with the experiments.","Made available in DSpace on 2011-05-07T13:55:23Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9712474.pdf: 6679842 bytes, checksum: 793b24b33be0a8cc73a5b88a075791db (MD5) Previous issue date: 1996","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T15:00:49Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:28:48-05:00 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"],"dc:identifier":["9780591199567","AAI9712474","(UMI)AAI9712474","http://hdl.handle.net/2142/22905"],"dc:language":["eng"],"dc:rights":["Copyright 1996 Wang, Gang"],"dc:subject":["Engineering, Mechanical","Computer Science"],"dc:title":["Large eddy simulations of bluff-body wakes on parallel computers"],"dc:type":["text"],"thesis:degree_discipline":["Mechanical Science and Engineering"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:20Z"}