The influence of blade curvature and helical blade twist on the performance of a vertical-axis wind turbine

Frank Scheurich, Timothy M. Fletcher, R.E. Brown

Research output: Contribution to conferencePaper

13 Citations (Scopus)

Abstract

Accurate aerodynamic modeling of vertical-axis wind turbines poses a significant challenge, but is essential if the performance of such turbines is to be predicted reliably. The rotation of the turbine induces large variations in the angle of attack of its blades that canmanifest as dynamic stall. In addition, interactions between the blades of the turbine and the wake that they produce can exacerbate dynamic stall and result in impulsive changes to the aerodynamic loading on the blades. The Vorticity Transport Model has been used to simulate the aerodynamic performance and wake dynamics of vertical-axis wind turbines with straight-bladed, curved-bladed and helically twisted configuration. It is known that vertical-axis wind turbines with either straight or curved blades deliver torque to their shaft that fluctuates at the blade passage frequency of the rotor. In contrast, a rotor with helically twisted blades delivers a relatively steady torque to the shaft. In the present paper, the interactions between helically twisted blades and the vortices within their wake are shown to result in localized perturbations to the aerodynamic loading on the rotor that can disrupt the otherwise relatively smooth power output that is predicted by simplistic aerodynamic tools that do not model the wake to sufficient fidelity. Furthermore, vertical-axis wind turbines with curved blades are shown to be somewhat more susceptible to local dynamic stall than turbines with straight blades.
LanguageEnglish
Publication statusPublished - 4 Jan 2010
Event29th ASME Wind Energy Symposium - Orlando, Florida
Duration: 4 Jan 20107 Jan 2010

Conference

Conference29th ASME Wind Energy Symposium
CityOrlando, Florida
Period4/01/107/01/10

Fingerprint

Wind turbines
Turbomachine blades
Aerodynamics
Turbines
Rotors
Torque
Angle of attack
Vorticity
Vortex flow

Keywords

  • vertical-axis wind turbines
  • dynamic stall
  • aerodynamic loading
  • vorticity transport model
  • wake dynamics

Cite this

Scheurich, F., Fletcher, T. M., & Brown, R. E. (2010). The influence of blade curvature and helical blade twist on the performance of a vertical-axis wind turbine. Paper presented at 29th ASME Wind Energy Symposium, Orlando, Florida, .
Scheurich, Frank ; Fletcher, Timothy M. ; Brown, R.E. / The influence of blade curvature and helical blade twist on the performance of a vertical-axis wind turbine. Paper presented at 29th ASME Wind Energy Symposium, Orlando, Florida, .
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Scheurich, F, Fletcher, TM & Brown, RE 2010, 'The influence of blade curvature and helical blade twist on the performance of a vertical-axis wind turbine' Paper presented at 29th ASME Wind Energy Symposium, Orlando, Florida, 4/01/10 - 7/01/10, .

The influence of blade curvature and helical blade twist on the performance of a vertical-axis wind turbine. / Scheurich, Frank; Fletcher, Timothy M.; Brown, R.E.

2010. Paper presented at 29th ASME Wind Energy Symposium, Orlando, Florida, .

Research output: Contribution to conferencePaper

TY - CONF

T1 - The influence of blade curvature and helical blade twist on the performance of a vertical-axis wind turbine

AU - Scheurich, Frank

AU - Fletcher, Timothy M.

AU - Brown, R.E.

PY - 2010/1/4

Y1 - 2010/1/4

N2 - Accurate aerodynamic modeling of vertical-axis wind turbines poses a significant challenge, but is essential if the performance of such turbines is to be predicted reliably. The rotation of the turbine induces large variations in the angle of attack of its blades that canmanifest as dynamic stall. In addition, interactions between the blades of the turbine and the wake that they produce can exacerbate dynamic stall and result in impulsive changes to the aerodynamic loading on the blades. The Vorticity Transport Model has been used to simulate the aerodynamic performance and wake dynamics of vertical-axis wind turbines with straight-bladed, curved-bladed and helically twisted configuration. It is known that vertical-axis wind turbines with either straight or curved blades deliver torque to their shaft that fluctuates at the blade passage frequency of the rotor. In contrast, a rotor with helically twisted blades delivers a relatively steady torque to the shaft. In the present paper, the interactions between helically twisted blades and the vortices within their wake are shown to result in localized perturbations to the aerodynamic loading on the rotor that can disrupt the otherwise relatively smooth power output that is predicted by simplistic aerodynamic tools that do not model the wake to sufficient fidelity. Furthermore, vertical-axis wind turbines with curved blades are shown to be somewhat more susceptible to local dynamic stall than turbines with straight blades.

AB - Accurate aerodynamic modeling of vertical-axis wind turbines poses a significant challenge, but is essential if the performance of such turbines is to be predicted reliably. The rotation of the turbine induces large variations in the angle of attack of its blades that canmanifest as dynamic stall. In addition, interactions between the blades of the turbine and the wake that they produce can exacerbate dynamic stall and result in impulsive changes to the aerodynamic loading on the blades. The Vorticity Transport Model has been used to simulate the aerodynamic performance and wake dynamics of vertical-axis wind turbines with straight-bladed, curved-bladed and helically twisted configuration. It is known that vertical-axis wind turbines with either straight or curved blades deliver torque to their shaft that fluctuates at the blade passage frequency of the rotor. In contrast, a rotor with helically twisted blades delivers a relatively steady torque to the shaft. In the present paper, the interactions between helically twisted blades and the vortices within their wake are shown to result in localized perturbations to the aerodynamic loading on the rotor that can disrupt the otherwise relatively smooth power output that is predicted by simplistic aerodynamic tools that do not model the wake to sufficient fidelity. Furthermore, vertical-axis wind turbines with curved blades are shown to be somewhat more susceptible to local dynamic stall than turbines with straight blades.

KW - vertical-axis wind turbines

KW - dynamic stall

KW - aerodynamic loading

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M3 - Paper

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Scheurich F, Fletcher TM, Brown RE. The influence of blade curvature and helical blade twist on the performance of a vertical-axis wind turbine. 2010. Paper presented at 29th ASME Wind Energy Symposium, Orlando, Florida, .