{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/76796"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/76796","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Experimental Study of Wall Shear Stress Modification by Surface Coating: Pressure Drop Measurements in a Rectangular Channel","abstract":"Presented in this paper are experiments to test the hypothesis that drag reduction is possible over hydrophobic surfaces in the Wenzel state during laminar and turbulent flows. Quantification of surface drag reduction in rectangular channel flow over walls with specific hydrophobic or hydrophilic properties was obtained with pressure drop measurements along the channel for a range of Reynolds numbers between 350 and 5900. Several commercially available materials and coatings were chosen in order to span a range of contact angles between 30° and 135°. The results are within the bounds of the theoretical values calculated with the Colebrook equation, and do not show any reduction in wall shear stress as a function of material properties or surface chemistry. The differences between this experiment and others measuring pressure drop over hydrophobic surfaces is the macro-scale conditions and the hydrophobic surfaces being fully wetted. These experiments are further proof of the importance of a liquid-vapor interface for increasing the shear free area to produce drag reduction.","abstract_html":"Presented in this paper are experiments to test the hypothesis that drag reduction is possible over hydrophobic surfaces in the Wenzel state during laminar and turbulent flows. Quantification of surface drag reduction in rectangular channel flow over walls with specific hydrophobic or hydrophilic properties was obtained with pressure drop measurements along the channel for a range of Reynolds numbers between 350 and 5900. Several commercially available materials and coatings were chosen in order to span a range of contact angles between 30° and 135°. The results are within the bounds of the theoretical values calculated with the Colebrook equation, and do not show any reduction in wall shear stress as a function of material properties or surface chemistry. The differences between this experiment and others measuring pressure drop over hydrophobic surfaces is the macro-scale conditions and the hydrophobic surfaces being fully wetted. These experiments are further proof of the importance of a liquid-vapor interface for increasing the shear free area to produce drag reduction.","abstract_has_math":false,"creators":["Dominic, Justin"],"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":["Vlachos, Pavlos P.","Charonko, John J."],"committee_members":["Diller, Thomas E."],"year":2011,"date_issued":"2011-05-31","date_published":"2011-05-31","updated_at":"2026-07-22T22:20:32Z","subjects":["boundary layer","drag reduction","hydrophobicity","wetting"],"languages":["en_US"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-06102011-124812"],"render_values":[{"text":"etd-06102011-124812","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/76796","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Vlachos, Pavlos P.","Charonko, John J."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Diller, Thomas E."]},{"key":"dc:contributor.department","label":"Department","values":["Mechanical Engineering"]},{"key":"dc:creator","label":"Author","values":["Dominic, Justin"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2017-04-04T19:49:18Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2017-04-04T19:49:18Z","2016-09-27"]},{"key":"dc:date.issued","label":"Date","values":["2011-05-31"]},{"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":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["boundary layer","drag reduction","hydrophobicity","wetting"]}]},{"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.other","label":"Dc Identifier Other","values":["etd-06102011-124812"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/76796"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Presented in this paper are experiments to test the hypothesis that drag reduction is possible over hydrophobic surfaces in the Wenzel state during laminar and turbulent flows. Quantification of surface drag reduction in rectangular channel flow over walls with specific hydrophobic or hydrophilic properties was obtained with pressure drop measurements along the channel for a range of Reynolds numbers between 350 and 5900. Several commercially available materials and coatings were chosen in order to span a range of contact angles between 30° and 135°. The results are within the bounds of the theoretical values calculated with the Colebrook equation, and do not show any reduction in wall shear stress as a function of material properties or surface chemistry. The differences between this experiment and others measuring pressure drop over hydrophobic surfaces is the macro-scale conditions and the hydrophobic surfaces being fully wetted. These experiments are further proof of the importance of a liquid-vapor interface for increasing the shear free area to produce drag reduction."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:title","label":"Title","values":["Experimental Study of Wall Shear Stress Modification by Surface Coating: Pressure Drop Measurements in a Rectangular Channel"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Vlachos, Pavlos P.","Charonko, John J."],"dc:contributor.committeemember":["Diller, Thomas E."],"dc:contributor.department":["Mechanical Engineering"],"dc:creator":["Dominic, Justin"],"dc:date.accessioned":["2017-04-04T19:49:18Z"],"dc:date.available":["2017-04-04T19:49:18Z","2016-09-27"],"dc:date.issued":["2011-05-31"],"dc:description.abstract":["Presented in this paper are experiments to test the hypothesis that drag reduction is possible over hydrophobic surfaces in the Wenzel state during laminar and turbulent flows. 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