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dc.contributor.authorGuttag, Mark Andrew
dc.contributor.authorReis, Pedro Miguel
dc.date.accessioned2018-03-27T15:43:15Z
dc.date.available2018-03-27T15:43:15Z
dc.date.issued2017-12
dc.date.submitted2017-02
dc.identifier.issn2469-990X
dc.identifier.issn2469-9918
dc.identifier.urihttp://hdl.handle.net/1721.1/114398
dc.description.abstractWe study a mechanism for active aerodynamic drag reduction on morphable grooved cylinders, whose topography can be modified pneumatically. Our design is inspired by the morphology of the Saguaro cactus (Carnegiea gigantea), which possesses an array of axial grooves, thought to help reduce aerodynamic drag, thereby enhancing the structural robustness of the plant under wind loading. Our analog experimental samples comprise a spoked rigid skeleton with axial cavities, covered by a stretched elastomeric film. Decreasing the inner pressure of the sample produces axial grooves, whose depth can be accurately varied, on demand. First, we characterize the relation between groove depth and pneumatic loading through a combination of precision mechanical experiments and finite element simulations. Second, wind tunnel tests are used to measure the aerodynamic drag coefficient (as a function of Reynolds number) of the grooved samples, with different levels of periodicity and groove depths. We focus specifically on the drag crisis and systematically measure the associated minimum drag coefficient and the critical Reynolds number at which it occurs. The results are in agreement with the classic literature of rough cylinders, albeit with an unprecedented level of precision and resolution in varying topography using a single sample. Finally, we leverage the morphable nature of our system to dynamically reduce drag for varying aerodynamic loading conditions. We demonstrate that actively controlling the groove depth yields a drag coefficient that decreases monotonically with Reynolds number and is significantly lower than the fixed sample counterparts. These findings open the possibility for the drag reduction of grooved cylinders to be operated over a wide range of flow conditions.en_US
dc.description.sponsorshipNational Science Foundation (U.S.) (CAREER CMMI-1351449)en_US
dc.publisherAmerican Physical Societyen_US
dc.relation.isversionofhttp://dx.doi.org/10.1103/PhysRevFluids.2.123903en_US
dc.rightsArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.en_US
dc.sourceAmerican Physical Societyen_US
dc.titleActive aerodynamic drag reduction on morphable cylindersen_US
dc.typeArticleen_US
dc.identifier.citationGuttag, M. and P. M. Reis. "Active aerodynamic drag reduction on morphable cylinders." Physical Review Fluids 2, 12 (December 2017): 123903 © 2017 American Physical Societyen_US
dc.contributor.departmentMassachusetts Institute of Technology. Department of Civil and Environmental Engineeringen_US
dc.contributor.departmentMassachusetts Institute of Technology. Department of Mechanical Engineeringen_US
dc.contributor.mitauthorGuttag, Mark Andrew
dc.contributor.mitauthorReis, Pedro Miguel
dc.relation.journalPhysical Review Fluidsen_US
dc.eprint.versionFinal published versionen_US
dc.type.urihttp://purl.org/eprint/type/JournalArticleen_US
eprint.statushttp://purl.org/eprint/status/PeerRevieweden_US
dc.date.updated2018-02-07T20:55:52Z
dc.language.rfc3066en
dc.rights.holderAmerican Physical Society
dspace.orderedauthorsGuttag, M.; Reis, P. M.en_US
dspace.embargo.termsNen_US
dc.identifier.orcidhttps://orcid.org/0000-0002-0703-4989
dc.identifier.orcidhttps://orcid.org/0000-0003-3984-828X
mit.licensePUBLISHER_POLICYen_US


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