Vertical-axis wind turbines in oblique flow: sensitivity to rotor geometry

Frank Scheurich, Richard Brown

Research output: Contribution to conference › Paper

9 Citations (Scopus)

Abstract

Increasing interest is being shown worldwide in the application of vertical-axis wind turbines for decentralised electricity generation within cities. The distortion of the onset air flow by buildings within the urban environment might however, under certain conditions of wind speed or direction, cause vertical-axis wind turbines to operate in oblique flow – in other words in conditions in which the wind vector is non-perpendicular to the axis of rotation of the turbine. Little is known about the effect on the operation of a vertical-axis wind turbine when the wind is perturbed from supposedly optimal conditions. In the present study, the Vorticity Transport Model has been used to simulate the aerodynamic performance and wake dynamics, both in normal and in oblique flow, of three different vertical-axis wind turbines: one with a straight-bladed configuration, another with a curved-bladed configuration and another with a helically twisted configuration. The results partly confirm previous experimental measurements that suggest that a straight-bladed vertical-axis wind turbine that operates in oblique flow might produce a higher power coefficient compared to when it is operated in normal flow. The simulations suggest, however, that significantly higher power coefficients in oblique flow are obtained only at higher tip speed ratios, and indeed only if the height of the turbine is not large compared to its radius. Furthermore, it is shown that a vertical-axis wind turbine with blades that are helically twisted around its rotational axis produces a relatively steady power coefficient in both normal and oblique flow when compared to that produced by turbines with either a straight- or a curved-bladed configuration.
LanguageEnglish
Number of pages8
Publication statusPublished - 14 Mar 2011
EventEWEA Annual event (formerly known as EWEC) - Brussels, Belgium
Duration: 14 Mar 2011 → 17 Mar 2011

Conference

ConferenceEWEA Annual event (formerly known as EWEC)
CountryBelgium
CityBrussels
Period14/03/11 → 17/03/11

Fingerprint

Wind Turbine
Oblique
Wind turbines
Rotor
Rotors
Vertical
Geometry
Turbines
Turbine
Straight
Configuration
High Power
Coefficient
Vorticity
Turbomachine blades
Aerodynamics
Wind Speed
Electricity
Wake
Blade

Keywords

  • vertical-axis wind turbine
  • oblique flow
  • numerical modelling
  • vorticity transport model

Cite this

Scheurich, F., & Brown, R. (2011). Vertical-axis wind turbines in oblique flow: sensitivity to rotor geometry. Paper presented at EWEA Annual event (formerly known as EWEC), Brussels, Belgium.
Scheurich, Frank ; Brown, Richard. / Vertical-axis wind turbines in oblique flow: sensitivity to rotor geometry. Paper presented at EWEA Annual event (formerly known as EWEC), Brussels, Belgium.8 p.
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Scheurich, F & Brown, R 2011, 'Vertical-axis wind turbines in oblique flow: sensitivity to rotor geometry' Paper presented at EWEA Annual event (formerly known as EWEC), Brussels, Belgium, 14/03/11 - 17/03/11, .

Vertical-axis wind turbines in oblique flow: sensitivity to rotor geometry. / Scheurich, Frank; Brown, Richard.

2011. Paper presented at EWEA Annual event (formerly known as EWEC), Brussels, Belgium.

Research output: Contribution to conference › Paper

TY - CONF

T1 - Vertical-axis wind turbines in oblique flow: sensitivity to rotor geometry

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AU - Brown, Richard

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AB - Increasing interest is being shown worldwide in the application of vertical-axis wind turbines for decentralised electricity generation within cities. The distortion of the onset air flow by buildings within the urban environment might however, under certain conditions of wind speed or direction, cause vertical-axis wind turbines to operate in oblique flow – in other words in conditions in which the wind vector is non-perpendicular to the axis of rotation of the turbine. Little is known about the effect on the operation of a vertical-axis wind turbine when the wind is perturbed from supposedly optimal conditions. In the present study, the Vorticity Transport Model has been used to simulate the aerodynamic performance and wake dynamics, both in normal and in oblique flow, of three different vertical-axis wind turbines: one with a straight-bladed configuration, another with a curved-bladed configuration and another with a helically twisted configuration. The results partly confirm previous experimental measurements that suggest that a straight-bladed vertical-axis wind turbine that operates in oblique flow might produce a higher power coefficient compared to when it is operated in normal flow. The simulations suggest, however, that significantly higher power coefficients in oblique flow are obtained only at higher tip speed ratios, and indeed only if the height of the turbine is not large compared to its radius. Furthermore, it is shown that a vertical-axis wind turbine with blades that are helically twisted around its rotational axis produces a relatively steady power coefficient in both normal and oblique flow when compared to that produced by turbines with either a straight- or a curved-bladed configuration.

KW - vertical-axis wind turbine

KW - oblique flow

KW - numerical modelling

KW - vorticity transport model

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Scheurich F, Brown R. Vertical-axis wind turbines in oblique flow: sensitivity to rotor geometry. 2011. Paper presented at EWEA Annual event (formerly known as EWEC), Brussels, Belgium.

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