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dc.contributor.authorShafer, Daniel Manfreden_US
dc.date.accessioned2014-03-14T20:35:49Z
dc.date.available2014-03-14T20:35:49Z
dc.date.issued2005-04-27en_US
dc.identifier.otheretd-05092005-165137en_US
dc.identifier.urihttp://hdl.handle.net/10919/32427
dc.description.abstractHelicopter operations in the vicinity of small naval surface vessels often require excessive pilot workload. Because of the unsteady flow field and large mean velocity gradients, the envelope for flight operations is limited. This experimental investigation uses a 1:144 scale model of the U.S. Navy destroyer DDG-81 to explore the problem. Both active and passive flow control techniques were used to improve the flow field in the helicopterâ s final decent onto the flight deck. Wind tunnel data was collected at a set of grid points over the shipâ s flight deck using a single component hotwire. Results show that the use of porous surfaces decreases the unsteadiness of the flow field. Further improvements are found by injecting air through these porous surfaces, causing a reduction in unsteadiness in the landing region of 6.6% at 0 degrees wind-over-deck (WOD) and 8.3% at 20 degrees WOD. Other passive configurations tested include fences placed around the hangar deck edges which move the unsteady shear layer away from the flight deck. Although these devices cause an increase in unsteadiness downstream of the edge of the fence when compared to the baseline, the reticulated foam fence caused an overall decrease in unsteadiness in the landing region of 12.1% at 20 degrees WOD.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartthesis_final.pdfen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectbackward facing stepen_US
dc.subjectfrigate ship airwakeen_US
dc.subjectflow controlen_US
dc.subjecthelicopter/ship operationsen_US
dc.subjectairwakeen_US
dc.titleActive and Passive Flow Control over the Flight Deck of Small Naval Vesselsen_US
dc.typeThesisen_US
dc.contributor.departmentAerospace and Ocean Engineeringen_US
dc.description.degreeMaster of Scienceen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.levelmastersen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineAerospace and Ocean Engineeringen_US
dc.contributor.committeechairMason, William H.en_US
dc.contributor.committeememberDevenport, William J.en_US
dc.contributor.committeememberFindlay, David B.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-05092005-165137/en_US
dc.date.sdate2005-05-09en_US
dc.date.rdate2005-05-16
dc.date.adate2005-05-16en_US


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