Effects of surface roughness and wall confinement on bluff body aerodynamics at large-gap regime

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MetadadosDescriçãoIdioma
Autor(es): dc.contributorFederal University of Itajubá (UNIFEI)-
Autor(es): dc.contributorUniversidade Estadual Paulista (UNESP)-
Autor(es): dc.creatorde Moraes, Paulo Guimarães-
Autor(es): dc.creatorde Oliveira, Marcos André-
Autor(es): dc.creatorde Andrade, Crystianne Lilian-
Autor(es): dc.creatorBimbato, Alex Mendonça [UNESP]-
Autor(es): dc.creatorAlcântara Pereira, Luiz Antonio-
Data de aceite: dc.date.accessioned2022-08-04T22:10:43Z-
Data de disponibilização: dc.date.available2022-08-04T22:10:43Z-
Data de envio: dc.date.issued2022-04-28-
Data de envio: dc.date.issued2022-04-28-
Data de envio: dc.date.issued2021-08-01-
Fonte completa do material: dc.identifierhttp://dx.doi.org/10.1007/s40430-021-03111-4-
Fonte completa do material: dc.identifierhttp://hdl.handle.net/11449/222062-
Fonte: dc.identifier.urihttp://educapes.capes.gov.br/handle/11449/222062-
Descrição: dc.descriptionA purely Lagrangian vortex method is employed to investigate turbulent flows past a rough circular cylinder under moving wall effect at large-gap regime, namely h*/d* = 0.45 and 0.80 (h* establishes the gap height between the moving wall base and the cylinder underside, and d* defines the outer cylinder diameter), yielding data in a transition regime, between the supercritical and transcritical regimes. In the large-gap regime, strong vortical structures are cyclically generated at the rear part of the cylinder. The numerical simulations utilize a two-dimensional model to simulate surface roughness effect. That model is inspired in a point set strategically located close to a body surface to inject momentum in its boundary layer and thus to capture a delay in the separation point of flow. Special attention is directed toward the relative roughness size variation, being that each test case always starts from an upper-subcritical Reynolds number of Re = 1.0 × 105. The present work contributes in the literature: (i) providing a detailed study of temporal evolution of pressure distribution, simultaneously computed with the integrated aerodynamic loads (drag and lift forces), Strouhal number and angle of boundary layer separation and (ii) examining the possibility of predicting suppression of vortex shedding. Such approach has been successfully applied within the study of bluff body aerodynamics at small-gap regime (i.e., h*/d* < 0.25), where the vortex shedding frequency completely disappears. Overall, the results reveal the sensitivity of the numerical technique to capture changes on the aerodynamic characteristics of a cylinder. For test with the rougher cylinder at h*/d* = 0.45, the big and small peaks on the drag curve are more influenced by increasing of noises because of surface roughness effect; consequently, the drag curve oscillates around small values reducing the mean drag coefficient. A drag reduction around 13% is identified as compared to a smooth cylinder. The lift force also reduces and still remains positive. The position of the separation points of the flow also changes, which characterizes boundary layer detachment with delay. The results are substantiated by a greater base pressure of the rougher cylinder; furthermore, only small differences are identified in the base pressure between both smooth and less rough cylinders, which explains the nearly constant level of drag force on them.-
Descrição: dc.descriptionFundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)-
Descrição: dc.descriptionMechanical Engineering Institute Federal University of Itajubá (UNIFEI)-
Descrição: dc.descriptionSchool of Engineering São Paulo State University (UNESP)-
Descrição: dc.descriptionSchool of Engineering São Paulo State University (UNESP)-
Descrição: dc.descriptionFAPEMIG: APQ-02175-14-
Idioma: dc.languageen-
Relação: dc.relationJournal of the Brazilian Society of Mechanical Sciences and Engineering-
???dc.source???: dc.sourceScopus-
Palavras-chave: dc.subjectBluff body-
Palavras-chave: dc.subjectLagrangian manner-
Palavras-chave: dc.subjectLarge-gap regime-
Palavras-chave: dc.subjectSuppression-
Palavras-chave: dc.subjectSurface roughness effect-
Título: dc.titleEffects of surface roughness and wall confinement on bluff body aerodynamics at large-gap regime-
Tipo de arquivo: dc.typelivro digital-
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