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dc.contributor.authorGómez-De-Segura, Gen
dc.contributor.authorGarcía-Mayoral, Ren
dc.date.accessioned2019-06-10T23:30:25Z
dc.date.available2019-06-10T23:30:25Z
dc.date.issued2019-01-01en
dc.identifier.issn1469-7645
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/293517
dc.description.abstractWe explore the ability of anisotropic permeable substrates to reduce turbulent skinfriction, studying the influence that these substrates have on the overlying turbulence. For this, we perform DNSs of channel flows bounded by permeable substrates. The results confirm theoretical predictions, and the resulting drag curves are similar to those of riblets. For small permeabilities, the drag reduction is proportional to the difference between the streamwise and spanwise permeabilities. This linear regime breaks down for a critical value of the wall-normal permeability, beyond which the performance begins to degrade. We observe that the degradation is associated with the appearance of spanwisecoherent structures, attributed to a Kelvin-Helmholtz-like instability of the mean flow. This feature is common to a variety of obstructed flows, and linear stability analysis can be used to predict it. For large permeabilities, these structures become prevalent in the flow, outweighing the drag-reducing effect of slip and eventually leading to an increase of drag. For the substrate configurations considered, the largest drag reduction observed is ≈ 20−25% at a friction Reynolds number δ+ = 180.
dc.description.sponsorshipFundacion Bancaria ‘la Caixa’, Zonta - Amelia Earhart Fellowship, Cambridge Commonwealth, European and International Trust
dc.publisherCambridge University Press
dc.rightsAll rights reserved
dc.titleTurbulent drag reduction curves for anisotropic permeable substrates – Analysis and direct numerical simulationsen
dc.typeConference Object
prism.publicationDate2019en
prism.publicationName11th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2019en
dc.identifier.doi10.17863/CAM.40655
dcterms.dateAccepted2019-06-04en
rioxxterms.versionAM
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserveden
rioxxterms.licenseref.startdate2019-01-01en
rioxxterms.typeConference Paper/Proceeding/Abstracten
cam.orpheus.successThu Nov 05 11:54:04 GMT 2020 - Embargo updated*
rioxxterms.freetoread.startdate2020-01-01


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