{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/45783"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/45783","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"On subharmonic instability in boundary layers","abstract":"The subharmonic instability in two-dimensional boundary layer on a flat plate is analyzed using the parametric instability model and the resonant triad model. The problems arising from both models are solved numerically using the shooting technique and results are presented. It is found that in the presence of a strong interaction (e.g., large amplitude of the two-dimensional wave), results from the resonant triad model are inaccurate as compared with the experimental data and the t results from the parametric instability model. This is mainly because the resonant triad model is a weakly nonlinear model, and it does not account for the modification of the eigenfunctions of the interacting waves which really takes place as we find out from the experiments. The parametric instability model is a powerful model, despite all the assumptions included. The model, however, does not introduce a clear understanding of how the subharmonic mode originates from the three-dimensional Tollmien-Schlichting modes. For a weak interaction results from the resonant triad model and the parametric instability model get close to each other.","abstract_html":"The subharmonic instability in two-dimensional boundary layer on a flat plate is analyzed using the parametric instability model and the resonant triad model. The problems arising from both models are solved numerically using the shooting technique and results are presented. It is found that in the presence of a strong interaction (e.g., large amplitude of the two-dimensional wave), results from the resonant triad model are inaccurate as compared with the experimental data and the t results from the parametric instability model. This is mainly because the resonant triad model is a weakly nonlinear model, and it does not account for the modification of the eigenfunctions of the interacting waves which really takes place as we find out from the experiments. The parametric instability model is a powerful model, despite all the assumptions included. The model, however, does not introduce a clear understanding of how the subharmonic mode originates from the three-dimensional Tollmien-Schlichting modes. For a weak interaction results from the resonant triad model and the parametric instability model get close to each other.","abstract_has_math":false,"creators":["Masad, Jamal A."],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Engineering Mechanics","degree_department":"Engineering Mechanics","school":null,"contributors":[],"advisors":[],"committee_chairs":["Nayfeh, Ali H."],"committee_members":["Mook, Dean T.","Ragab, Saad A."],"year":1987,"date_issued":"1987-12-05","date_published":"1987-12-05","updated_at":"2026-07-22T22:20:02Z","subjects":[],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-11172012-040114"],"render_values":[{"text":"etd-11172012-040114","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/45783","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Nayfeh, Ali H."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Mook, Dean T.","Ragab, Saad A."]},{"key":"dc:contributor.department","label":"Department","values":["Engineering Mechanics"]},{"key":"dc:creator","label":"Author","values":["Masad, Jamal A."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-03-14T21:49:54Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-03-14T21:49:54Z","2012-11-17"]},{"key":"dc:date.issued","label":"Date","values":["1987-12-05"]},{"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":["Engineering Mechanics"]},{"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: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-11172012-040114"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/45783"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The subharmonic instability in two-dimensional boundary layer on a flat plate is analyzed using the parametric instability model and the resonant triad model. The problems arising from both models are solved numerically using the shooting technique and results are presented. It is found that in the presence of a strong interaction (e.g., large amplitude of the two-dimensional wave), results from the resonant triad model are inaccurate as compared with the experimental data and the t results from the parametric instability model. This is mainly because the resonant triad model is a weakly nonlinear model, and it does not account for the modification of the eigenfunctions of the interacting waves which really takes place as we find out from the experiments. The parametric instability model is a powerful model, despite all the assumptions included. The model, however, does not introduce a clear understanding of how the subharmonic mode originates from the three-dimensional Tollmien-Schlichting modes. For a weak interaction results from the resonant triad model and the parametric instability model get close to each other."]},{"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":["On subharmonic instability in boundary layers"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Nayfeh, Ali H."],"dc:contributor.committeemember":["Mook, Dean T.","Ragab, Saad A."],"dc:contributor.department":["Engineering Mechanics"],"dc:creator":["Masad, Jamal A."],"dc:date.accessioned":["2014-03-14T21:49:54Z"],"dc:date.available":["2014-03-14T21:49:54Z","2012-11-17"],"dc:date.issued":["1987-12-05"],"dc:description.abstract":["The subharmonic instability in two-dimensional boundary layer on a flat plate is analyzed using the parametric instability model and the resonant triad model. The problems arising from both models are solved numerically using the shooting technique and results are presented. It is found that in the presence of a strong interaction (e.g., large amplitude of the two-dimensional wave), results from the resonant triad model are inaccurate as compared with the experimental data and the t results from the parametric instability model. This is mainly because the resonant triad model is a weakly nonlinear model, and it does not account for the modification of the eigenfunctions of the interacting waves which really takes place as we find out from the experiments. The parametric instability model is a powerful model, despite all the assumptions included. The model, however, does not introduce a clear understanding of how the subharmonic mode originates from the three-dimensional Tollmien-Schlichting modes. 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