{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/43152"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/43152","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"The simultaneous measurement of time-resolved surface heat flux and freestream turbulence at a stagnation point","abstract":"Two rapid-response thin-film heat flux gage systems have been used to measure time-resolved unsteady heat transfer signals. The Heat Flux Microsensor is a passive gage which measures the temperature difference across a thin thermal resistance. The second sensor, an actively powered gage operated by a constant temperature anemometer, measures heat flux by measuring dissipated power. These gages have frequency performance windows of 50 kHz and 250 Hz, respectively. Each gage was calibrated for both steady and unsteady response. They were then placed at a flow stagnation point. A velocity probe is positioned outside the boundary layer adjacent to the gage. Simultaneous monitoring of these signals allowed the time-resolved documentation of the effects of local freestream turbulence on boundary layer heat transfer. The resulting time traces indicate a direct correlation between the turbulent velocity fluctuations and heat flux variation. The effects of apparent single-frequency turbulent components are isolated on both the velocity and heat flux signals. These signals are analyzed to determine their relative amplitude and phase characteristics. The results are compared to similar relationships characterized in regularly pulsating laminar flow regimes.","abstract_html":"Two rapid-response thin-film heat flux gage systems have been used to measure time-resolved unsteady heat transfer signals. The Heat Flux Microsensor is a passive gage which measures the temperature difference across a thin thermal resistance. The second sensor, an actively powered gage operated by a constant temperature anemometer, measures heat flux by measuring dissipated power. These gages have frequency performance windows of 50 kHz and 250 Hz, respectively. Each gage was calibrated for both steady and unsteady response. They were then placed at a flow stagnation point. A velocity probe is positioned outside the boundary layer adjacent to the gage. Simultaneous monitoring of these signals allowed the time-resolved documentation of the effects of local freestream turbulence on boundary layer heat transfer. The resulting time traces indicate a direct correlation between the turbulent velocity fluctuations and heat flux variation. The effects of apparent single-frequency turbulent components are isolated on both the velocity and heat flux signals. These signals are analyzed to determine their relative amplitude and phase characteristics. The results are compared to similar relationships characterized in regularly pulsating laminar flow regimes.","abstract_has_math":false,"creators":["Simmons, Stephen Gordon"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Mechanical Engineering","degree_department":"Mechanical Engineering","school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1990,"date_issued":"1990","date_published":"1990","updated_at":"2026-07-22T22:20:02Z","subjects":[],"languages":["en"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-06112009-063356"],"render_values":[{"text":"etd-06112009-063356","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/43152","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.department","label":"Department","values":["Mechanical Engineering"]},{"key":"dc:creator","label":"Author","values":["Simmons, Stephen Gordon"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-03-14T21:37:56Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-03-14T21:37:56Z","2009-06-11"]},{"key":"dc:date.issued","label":"Date","values":["1990"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.dcmitype","label":"Dc Type Dcmitype","values":["Text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Mechanical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-06112009-063356"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/43152"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Two rapid-response thin-film heat flux gage systems have been used to measure time-resolved unsteady heat transfer signals. The Heat Flux Microsensor is a passive gage which measures the temperature difference across a thin thermal resistance. The second sensor, an actively powered gage operated by a constant temperature anemometer, measures heat flux by measuring dissipated power. These gages have frequency performance windows of 50 kHz and 250 Hz, respectively. Each gage was calibrated for both steady and unsteady response. They were then placed at a flow stagnation point. A velocity probe is positioned outside the boundary layer adjacent to the gage. Simultaneous monitoring of these signals allowed the time-resolved documentation of the effects of local freestream turbulence on boundary layer heat transfer. The resulting time traces indicate a direct correlation between the turbulent velocity fluctuations and heat flux variation. The effects of apparent single-frequency turbulent components are isolated on both the velocity and heat flux signals. These signals are analyzed to determine their relative amplitude and phase characteristics. The results are compared to similar relationships characterized in regularly pulsating laminar flow regimes."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["BTD"]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["The simultaneous measurement of time-resolved surface heat flux and freestream turbulence at a stagnation point"]}]}],"canonical_facts":{"dc:contributor.department":["Mechanical Engineering"],"dc:creator":["Simmons, Stephen Gordon"],"dc:date.accessioned":["2014-03-14T21:37:56Z"],"dc:date.available":["2014-03-14T21:37:56Z","2009-06-11"],"dc:date.issued":["1990"],"dc:description.abstract":["Two rapid-response thin-film heat flux gage systems have been used to measure time-resolved unsteady heat transfer signals. The Heat Flux Microsensor is a passive gage which measures the temperature difference across a thin thermal resistance. The second sensor, an actively powered gage operated by a constant temperature anemometer, measures heat flux by measuring dissipated power. These gages have frequency performance windows of 50 kHz and 250 Hz, respectively. Each gage was calibrated for both steady and unsteady response. They were then placed at a flow stagnation point. A velocity probe is positioned outside the boundary layer adjacent to the gage. Simultaneous monitoring of these signals allowed the time-resolved documentation of the effects of local freestream turbulence on boundary layer heat transfer. The resulting time traces indicate a direct correlation between the turbulent velocity fluctuations and heat flux variation. The effects of apparent single-frequency turbulent components are isolated on both the velocity and heat flux signals. These signals are analyzed to determine their relative amplitude and phase characteristics. The results are compared to similar relationships characterized in regularly pulsating laminar flow regimes."],"dc:description.degree":["Master of Science"],"dc:format.medium":["BTD"],"dc:format.mimetype":["application/pdf"],"dc:identifier.other":["etd-06112009-063356"],"dc:identifier.uri":["http://hdl.handle.net/10919/43152"],"dc:language.iso":["en"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:title":["The simultaneous measurement of time-resolved surface heat flux and freestream turbulence at a stagnation point"],"dc:type":["Thesis"],"dc:type.dcmitype":["Text"],"thesis:degree_discipline":["Mechanical Engineering"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:20:02Z"}