Experimental investigation of an airfoil response under stall-induced pitching oscillations

Detalhes bibliográficos
Autor(a) principal: Pereira, Daniel A.
Data de Publicação: 2016
Outros Autores: Vasconcellos, Rui M. G. [UNESP], Marques, Flávio D.
Tipo de documento: Artigo de conferência
Idioma: eng
Título da fonte: Repositório Institucional da UNESP
Texto Completo: http://hdl.handle.net/11449/168398
Resumo: In this work, an investigation on the embedded dynamics of experimental aeroelastic signals of an airfoil under the influence of stall-induced oscillations is presented. Helicopter blades or wind turbines are examples of real aeroelastic surfaces that severely vibrate in stall conditions, leading to problems that motivates this research. Despite significant efforts to model the aerodynamics associated with the stall phenomenon, non-linear aeroelastic behavior prediction and analysis in such flow regime remains a challenge. This modeling requires proper knowledge of the physical events during stall regime, such knowledge can be better attained from experimental data. In this work a pitching airfoil is tested in a wind tunnel model. The aeroelastic signals are acquired using an optical angular encoder and the data is evaluated applying techniques from time series theory as the state space reconstruction, Poincaré sections and bifurcation analysis. The method of Singular Value Decomposition (SVD) is used to reconstruct the state space, revealing indications to possible bifurcations and complex dynamics. Changes in amplitudes of stall-induced oscillation due to airspeed and preset angles increases were also investigated. The results show that the airfoil presents sustained periodic and limit cycle oscillations at high angles of attack due to the stall influence. For the different preset angles, the appearance of the second bifurcation changes the range of oscillations, from asymmetric to symmetric with a significant increase in the amplitude. It is shown that the system complexity is mostly dependent on the aerodynamic flow conditions that override possible nonlinear structural effects and direct the airfoil to present significant stall-induced oscillations.
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spelling Experimental investigation of an airfoil response under stall-induced pitching oscillationsIn this work, an investigation on the embedded dynamics of experimental aeroelastic signals of an airfoil under the influence of stall-induced oscillations is presented. Helicopter blades or wind turbines are examples of real aeroelastic surfaces that severely vibrate in stall conditions, leading to problems that motivates this research. Despite significant efforts to model the aerodynamics associated with the stall phenomenon, non-linear aeroelastic behavior prediction and analysis in such flow regime remains a challenge. This modeling requires proper knowledge of the physical events during stall regime, such knowledge can be better attained from experimental data. In this work a pitching airfoil is tested in a wind tunnel model. The aeroelastic signals are acquired using an optical angular encoder and the data is evaluated applying techniques from time series theory as the state space reconstruction, Poincaré sections and bifurcation analysis. The method of Singular Value Decomposition (SVD) is used to reconstruct the state space, revealing indications to possible bifurcations and complex dynamics. Changes in amplitudes of stall-induced oscillation due to airspeed and preset angles increases were also investigated. The results show that the airfoil presents sustained periodic and limit cycle oscillations at high angles of attack due to the stall influence. For the different preset angles, the appearance of the second bifurcation changes the range of oscillations, from asymmetric to symmetric with a significant increase in the amplitude. It is shown that the system complexity is mostly dependent on the aerodynamic flow conditions that override possible nonlinear structural effects and direct the airfoil to present significant stall-induced oscillations.Engineering School of São Carlos University of São PauloSão Paulo State University (UNESP) São João da Boa VistaSão Paulo State University (UNESP) São João da Boa VistaUniversidade de São Paulo (USP)Universidade Estadual Paulista (Unesp)Pereira, Daniel A.Vasconcellos, Rui M. G. [UNESP]Marques, Flávio D.2018-12-11T16:41:06Z2018-12-11T16:41:06Z2016-01-01info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/conferenceObject57th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference.http://hdl.handle.net/11449/1683982-s2.0-8495858223603479922475174420000-0001-7288-5408Scopusreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPeng57th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conferenceinfo:eu-repo/semantics/openAccess2021-10-22T18:56:37Zoai:repositorio.unesp.br:11449/168398Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462024-08-05T21:19:18.144337Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false
dc.title.none.fl_str_mv Experimental investigation of an airfoil response under stall-induced pitching oscillations
title Experimental investigation of an airfoil response under stall-induced pitching oscillations
spellingShingle Experimental investigation of an airfoil response under stall-induced pitching oscillations
Pereira, Daniel A.
title_short Experimental investigation of an airfoil response under stall-induced pitching oscillations
title_full Experimental investigation of an airfoil response under stall-induced pitching oscillations
title_fullStr Experimental investigation of an airfoil response under stall-induced pitching oscillations
title_full_unstemmed Experimental investigation of an airfoil response under stall-induced pitching oscillations
title_sort Experimental investigation of an airfoil response under stall-induced pitching oscillations
author Pereira, Daniel A.
author_facet Pereira, Daniel A.
Vasconcellos, Rui M. G. [UNESP]
Marques, Flávio D.
author_role author
author2 Vasconcellos, Rui M. G. [UNESP]
Marques, Flávio D.
author2_role author
author
dc.contributor.none.fl_str_mv Universidade de São Paulo (USP)
Universidade Estadual Paulista (Unesp)
dc.contributor.author.fl_str_mv Pereira, Daniel A.
Vasconcellos, Rui M. G. [UNESP]
Marques, Flávio D.
description In this work, an investigation on the embedded dynamics of experimental aeroelastic signals of an airfoil under the influence of stall-induced oscillations is presented. Helicopter blades or wind turbines are examples of real aeroelastic surfaces that severely vibrate in stall conditions, leading to problems that motivates this research. Despite significant efforts to model the aerodynamics associated with the stall phenomenon, non-linear aeroelastic behavior prediction and analysis in such flow regime remains a challenge. This modeling requires proper knowledge of the physical events during stall regime, such knowledge can be better attained from experimental data. In this work a pitching airfoil is tested in a wind tunnel model. The aeroelastic signals are acquired using an optical angular encoder and the data is evaluated applying techniques from time series theory as the state space reconstruction, Poincaré sections and bifurcation analysis. The method of Singular Value Decomposition (SVD) is used to reconstruct the state space, revealing indications to possible bifurcations and complex dynamics. Changes in amplitudes of stall-induced oscillation due to airspeed and preset angles increases were also investigated. The results show that the airfoil presents sustained periodic and limit cycle oscillations at high angles of attack due to the stall influence. For the different preset angles, the appearance of the second bifurcation changes the range of oscillations, from asymmetric to symmetric with a significant increase in the amplitude. It is shown that the system complexity is mostly dependent on the aerodynamic flow conditions that override possible nonlinear structural effects and direct the airfoil to present significant stall-induced oscillations.
publishDate 2016
dc.date.none.fl_str_mv 2016-01-01
2018-12-11T16:41:06Z
2018-12-11T16:41:06Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
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status_str publishedVersion
dc.identifier.uri.fl_str_mv 57th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference.
http://hdl.handle.net/11449/168398
2-s2.0-84958582236
0347992247517442
0000-0001-7288-5408
identifier_str_mv 57th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference.
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0347992247517442
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url http://hdl.handle.net/11449/168398
dc.language.iso.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv 57th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
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reponame:Repositório Institucional da UNESP
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reponame_str Repositório Institucional da UNESP
collection Repositório Institucional da UNESP
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