{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/87759"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/87759","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"An Experimental Study of Momentum and Thermal Transport in Flow Through Smooth- and Rough-Wall Microchannels","abstract":"Local Nusselt number (Nu) for smooth-wall laminar flow in the range 200 ≤ Re ≤ Recr agree well with macroscale predictions in both the thermally-developing and -developed regimes With increasing roughness, while an enhancement in local Nu is noted in the thermally-developing regime, no measurable influence is observed upon attainment of a thermally-developed state. These observations are supported by temperature profiles which suggest that the thermal boundary layer may be regenerated locally by roughness in the thermal entrance region of the flow. In the transitional regime, mean temperature profiles for the smooth- and rough-wall cases show deviation from fully-developed laminar behavior for Re > Recr. Finally, estimates of bulk Nu indicate enhancement in convective heat transfer over the smooth-wall case with increasing surface roughness in the laminar, transitional and turbulent regimes, though the smooth-wall data are in excellent agreement with macroscale predictions for laminar and turbulent flow. While a shift in the transitional pathway of the thermal transport behavior toward lower Re appears partially attributable for this enhancement with increasing roughness, it appears that turbulent convection also contributes significantly once transition is initiated.","abstract_html":"Local Nusselt number (Nu) for smooth-wall laminar flow in the range 200 ≤ Re ≤ Recr agree well with macroscale predictions in both the thermally-developing and -developed regimes With increasing roughness, while an enhancement in local Nu is noted in the thermally-developing regime, no measurable influence is observed upon attainment of a thermally-developed state. These observations are supported by temperature profiles which suggest that the thermal boundary layer may be regenerated locally by roughness in the thermal entrance region of the flow. In the transitional regime, mean temperature profiles for the smooth- and rough-wall cases show deviation from fully-developed laminar behavior for Re > Recr. Finally, estimates of bulk Nu indicate enhancement in convective heat transfer over the smooth-wall case with increasing surface roughness in the laminar, transitional and turbulent regimes, though the smooth-wall data are in excellent agreement with macroscale predictions for laminar and turbulent flow. While a shift in the transitional pathway of the thermal transport behavior toward lower Re appears partially attributable for this enhancement with increasing roughness, it appears that turbulent convection also contributes significantly once transition is initiated.","abstract_has_math":false,"creators":["Natrajan, Vinay Kumar"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Theoretical and Applied Mechanics","degree_department":null,"school":null,"contributors":["Christensen, Kenneth T."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-09-28T16:23:50Z","date_published":"2015-09-28T16:23:50Z","updated_at":"2026-07-22T22:26:30Z","subjects":["Engineering, Mechanical"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(MiAaPQ)AAI3392236"],"render_values":[{"text":"(MiAaPQ)AAI3392236","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/87759","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Christensen, Kenneth T."]},{"key":"dc:creator","label":"Author","values":["Natrajan, Vinay Kumar"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2015-09-28T16:23:50Z","10000-01-01","2009"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Theoretical and Applied Mechanics"]},{"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"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/87759","(MiAaPQ)AAI3392236"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Local Nusselt number (Nu) for smooth-wall laminar flow in the range 200 ≤ Re ≤ Recr agree well with macroscale predictions in both the thermally-developing and -developed regimes With increasing roughness, while an enhancement in local Nu is noted in the thermally-developing regime, no measurable influence is observed upon attainment of a thermally-developed state. These observations are supported by temperature profiles which suggest that the thermal boundary layer may be regenerated locally by roughness in the thermal entrance region of the flow. In the transitional regime, mean temperature profiles for the smooth- and rough-wall cases show deviation from fully-developed laminar behavior for Re > Recr. Finally, estimates of bulk Nu indicate enhancement in convective heat transfer over the smooth-wall case with increasing surface roughness in the laminar, transitional and turbulent regimes, though the smooth-wall data are in excellent agreement with macroscale predictions for laminar and turbulent flow. While a shift in the transitional pathway of the thermal transport behavior toward lower Re appears partially attributable for this enhancement with increasing roughness, it appears that turbulent convection also contributes significantly once transition is initiated.","Made available in DSpace on 2015-09-28T16:23:50Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 3392236.pdf: 3804561 bytes, checksum: 95d879dab18aeabe8163fbc665222e8c (MD5) Previous issue date: 2009","Embargo set by: Seth Robbins for item 89040 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","210 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2009."]},{"key":"dc:title","label":"Title","values":["An Experimental Study of Momentum and Thermal Transport in Flow Through Smooth- and Rough-Wall Microchannels"]}]}],"canonical_facts":{"dc:contributor":["Christensen, Kenneth T."],"dc:creator":["Natrajan, Vinay Kumar"],"dc:date":["2015-09-28T16:23:50Z","10000-01-01","2009"],"dc:description":["Local Nusselt number (Nu) for smooth-wall laminar flow in the range 200 ≤ Re ≤ Recr agree well with macroscale predictions in both the thermally-developing and -developed regimes With increasing roughness, while an enhancement in local Nu is noted in the thermally-developing regime, no measurable influence is observed upon attainment of a thermally-developed state. These observations are supported by temperature profiles which suggest that the thermal boundary layer may be regenerated locally by roughness in the thermal entrance region of the flow. In the transitional regime, mean temperature profiles for the smooth- and rough-wall cases show deviation from fully-developed laminar behavior for Re > Recr. Finally, estimates of bulk Nu indicate enhancement in convective heat transfer over the smooth-wall case with increasing surface roughness in the laminar, transitional and turbulent regimes, though the smooth-wall data are in excellent agreement with macroscale predictions for laminar and turbulent flow. While a shift in the transitional pathway of the thermal transport behavior toward lower Re appears partially attributable for this enhancement with increasing roughness, it appears that turbulent convection also contributes significantly once transition is initiated.","Made available in DSpace on 2015-09-28T16:23:50Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 3392236.pdf: 3804561 bytes, checksum: 95d879dab18aeabe8163fbc665222e8c (MD5) Previous issue date: 2009","Embargo set by: Seth Robbins for item 89040 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","210 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2009."],"dc:identifier":["http://hdl.handle.net/2142/87759","(MiAaPQ)AAI3392236"],"dc:language":["eng"],"dc:subject":["Engineering, Mechanical"],"dc:title":["An Experimental Study of Momentum and Thermal Transport in Flow Through Smooth- and Rough-Wall Microchannels"],"dc:type":["text"],"thesis:degree_discipline":["Theoretical and Applied Mechanics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:26:30Z"}