{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/51913"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/51913","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Mean-flow measurements of a turbulent mixing layer from helium slot injection into a supersonic airstream","abstract":"This investigation studies the mixing in a shear layer developed from helium slot injection into a parallel supersonic airstream and compares the results to those of previous slot-injection tests. The objectives of this study include documenting the helium slot-injection flowfield; providing a baseline for use as a reference for future work; contributing representative and consistent data to the general database; and increasing understanding of shear layer dynamics, especially as a result of foreign-gas injection. The helium injectant exits the slot at y = 1.67, M₋₁ = 1.78, Pu = 0.892 atm, and Tu = 287° K tangentially to an airstream at y = 1.4, M∞= 3, Pt∞= 6.5 atm, and Tt∞= 282° K. The freestream has Re/cm = 5.4x10⁵ and a boundary-layer thickness of (δau/H) = 0.58. The pertinent ratios are (P₁/P∞) = 0.838, (U₁/U∞) = 2, and (P₁/P∞) = 0.1. The slot height H is 1.21 cm. Along with short-duration Schlieren and Shadowgraph photography, concentration, Pitot, cone-static, and stagnation-temperature measurements are taken at each of four streamwise stations (x H = 0.3, 4.2, 10.5, 21.1) to document the development of the mixing layer. ln light of the binary-gas mixture, local concentration information is required to reduce the data to pertinent mean-flow variables (M, p, U, pU, P, and T). As expected, slot injection in general shows poor initial penetration of the injectant into the freestream, and, thus, poor initial mixing. Nevertheless, the helium case shows better mixing than a similar air injection case of a previous experiment, as the mixing shear layer grows 25 percent larger than that in the air case by the last station. Also, about 30 percent more freestream air is entrained into the shear layer in the helium case and is confined mainly to the top third of the mixing layer. The higher mixing rate stems from larger gradients in velocity and density and lower pU values which result in more active transport mechanisms in the helium injection test","abstract_html":"This investigation studies the mixing in a shear layer developed from helium slot injection into a parallel supersonic airstream and compares the results to those of previous slot-injection tests. The objectives of this study include documenting the helium slot-injection flowfield; providing a baseline for use as a reference for future work; contributing representative and consistent data to the general database; and increasing understanding of shear layer dynamics, especially as a result of foreign-gas injection. The helium injectant exits the slot at y = 1.67, M₋₁ = 1.78, P<sub>u</sub> = 0.892 atm, and T<sub>u</sub> = 287° K tangentially to an airstream at y = 1.4, M<sub>∞</sub>= 3, P<sub>t∞</sub>= 6.5 atm, and T<sub>t∞</sub>= 282° K. The freestream has Re/cm = 5.4x10⁵ and a boundary-layer thickness of (δ<sub>au</sub>/H) = 0.58. The pertinent ratios are (P₁/P<sub>∞</sub>) = 0.838, (U₁/U<sub>∞</sub>) = 2, and (P₁/P<sub>∞</sub>) = 0.1. The slot height H is 1.21 cm. Along with short-duration Schlieren and Shadowgraph photography, concentration, Pitot, cone-static, and stagnation-temperature measurements are taken at each of four streamwise stations (x H = 0.3, 4.2, 10.5, 21.1) to document the development of the mixing layer. ln light of the binary-gas mixture, local concentration information is required to reduce the data to pertinent mean-flow variables (M, p, U, pU, P, and T). As expected, slot injection in general shows poor initial penetration of the injectant into the freestream, and, thus, poor initial mixing. Nevertheless, the helium case shows better mixing than a similar air injection case of a previous experiment, as the mixing shear layer grows 25 percent larger than that in the air case by the last station. Also, about 30 percent more freestream air is entrained into the shear layer in the helium case and is confined mainly to the top third of the mixing layer. The higher mixing rate stems from larger gradients in velocity and density and lower pU values which result in more active transport mechanisms in the helium injection test","abstract_has_math":false,"creators":["Kwok, Fei Thomas"],"institution":"Virginia Polytechnic Institute and State University","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Aerospace Engineering","degree_department":"Aerospace Engineering","school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1989,"date_issued":"1989","date_published":"1989","updated_at":"2026-07-22T22:19:39Z","subjects":[],"languages":["en_US"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/10919/51913","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.department","label":"Department","values":["Aerospace Engineering"]},{"key":"dc:creator","label":"Author","values":["Kwok, Fei Thomas"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2015-04-29T18:10:15Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2015-04-29T18:10:15Z"]},{"key":"dc:date.issued","label":"Date","values":["1989"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Polytechnic Institute and State University"]},{"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":["Aerospace 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_US"]},{"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.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/51913"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["This investigation studies the mixing in a shear layer developed from helium slot injection into a parallel supersonic airstream and compares the results to those of previous slot-injection tests. The objectives of this study include documenting the helium slot-injection flowfield; providing a baseline for use as a reference for future work; contributing representative and consistent data to the general database; and increasing understanding of shear layer dynamics, especially as a result of foreign-gas injection. The helium injectant exits the slot at y = 1.67, M₋₁ = 1.78, Pu = 0.892 atm, and Tu = 287° K tangentially to an airstream at y = 1.4, M∞= 3, Pt∞= 6.5 atm, and Tt∞= 282° K. The freestream has Re/cm = 5.4x10⁵ and a boundary-layer thickness of (δau/H) = 0.58. The pertinent ratios are (P₁/P∞) = 0.838, (U₁/U∞) = 2, and (P₁/P∞) = 0.1. The slot height H is 1.21 cm. Along with short-duration Schlieren and Shadowgraph photography, concentration, Pitot, cone-static, and stagnation-temperature measurements are taken at each of four streamwise stations (x H = 0.3, 4.2, 10.5, 21.1) to document the development of the mixing layer. ln light of the binary-gas mixture, local concentration information is required to reduce the data to pertinent mean-flow variables (M, p, U, pU, P, and T). As expected, slot injection in general shows poor initial penetration of the injectant into the freestream, and, thus, poor initial mixing. Nevertheless, the helium case shows better mixing than a similar air injection case of a previous experiment, as the mixing shear layer grows 25 percent larger than that in the air case by the last station. Also, about 30 percent more freestream air is entrained into the shear layer in the helium case and is confined mainly to the top third of the mixing layer. The higher mixing rate stems from larger gradients in velocity and density and lower pU values which result in more active transport mechanisms in the helium injection test"]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Mean-flow measurements of a turbulent mixing layer from helium slot injection into a supersonic airstream"]}]}],"canonical_facts":{"dc:contributor.department":["Aerospace Engineering"],"dc:creator":["Kwok, Fei Thomas"],"dc:date.accessioned":["2015-04-29T18:10:15Z"],"dc:date.available":["2015-04-29T18:10:15Z"],"dc:date.issued":["1989"],"dc:description.abstract":["This investigation studies the mixing in a shear layer developed from helium slot injection into a parallel supersonic airstream and compares the results to those of previous slot-injection tests. The objectives of this study include documenting the helium slot-injection flowfield; providing a baseline for use as a reference for future work; contributing representative and consistent data to the general database; and increasing understanding of shear layer dynamics, especially as a result of foreign-gas injection. The helium injectant exits the slot at y = 1.67, M₋₁ = 1.78, Pu = 0.892 atm, and Tu = 287° K tangentially to an airstream at y = 1.4, M∞= 3, Pt∞= 6.5 atm, and Tt∞= 282° K. The freestream has Re/cm = 5.4x10⁵ and a boundary-layer thickness of (δau/H) = 0.58. The pertinent ratios are (P₁/P∞) = 0.838, (U₁/U∞) = 2, and (P₁/P∞) = 0.1. The slot height H is 1.21 cm. Along with short-duration Schlieren and Shadowgraph photography, concentration, Pitot, cone-static, and stagnation-temperature measurements are taken at each of four streamwise stations (x H = 0.3, 4.2, 10.5, 21.1) to document the development of the mixing layer. ln light of the binary-gas mixture, local concentration information is required to reduce the data to pertinent mean-flow variables (M, p, U, pU, P, and T). As expected, slot injection in general shows poor initial penetration of the injectant into the freestream, and, thus, poor initial mixing. Nevertheless, the helium case shows better mixing than a similar air injection case of a previous experiment, as the mixing shear layer grows 25 percent larger than that in the air case by the last station. Also, about 30 percent more freestream air is entrained into the shear layer in the helium case and is confined mainly to the top third of the mixing layer. The higher mixing rate stems from larger gradients in velocity and density and lower pU values which result in more active transport mechanisms in the helium injection test"],"dc:description.degree":["Master of Science"],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["http://hdl.handle.net/10919/51913"],"dc:language.iso":["en_US"],"dc:publisher":["Virginia Polytechnic Institute and State University"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:title":["Mean-flow measurements of a turbulent mixing layer from helium slot injection into a supersonic airstream"],"dc:type":["Thesis"],"dc:type.dcmitype":["Text"],"thesis:degree_discipline":["Aerospace Engineering"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:19:39Z"}