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Research Papers: Alternative Energy Sources

Effects From Complex Terrain on Wind-Turbine Performance

[+] Author and Article Information
Ann Hyvärinen

Department of Mechanics,
Linné FLOW Centre,
KTH Royal Institute of Technology,
Stockholm SE-100 44, Sweden
e-mail: annhy@mech.kth.se

Antonio Segalini

Department of Mechanics,
STandUP for Wind,
Linné FLOW Centre,
KTH Royal Institute of Technology,
Stockholm SE-100 44, Sweden
e-mail: segalini@mech.kth.se

1Corresponding author.

Contributed by the Advanced Energy Systems Division of ASME for publication in the JOURNAL OF ENERGY RESOURCES TECHNOLOGY. Manuscript received September 30, 2016; final manuscript received February 10, 2017; published online March 16, 2017. Assoc. Editor: Ryo Amano.

J. Energy Resour. Technol 139(5), 051205 (Mar 16, 2017) (10 pages) Paper No: JERT-16-1390; doi: 10.1115/1.4036048 History: Received September 30, 2016; Revised February 10, 2017

In this work, experimental measurements are made to study wind turbines over complex terrains and in presence of the atmospheric boundary layer. Thrust and power coefficients for single and multiple turbines are measured when introducing sinusoidal hills and spires inducing an artificial atmospheric boundary layer. Additionally, wake interaction effects are studied, and inflow velocity profiles are characterized using hot-wire anemometry. The results indicate that the introduced hills have a positive impact on the wind-turbine performance and that wake-interaction effects are significantly reduced during turbulent inflow conditions.

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Figures

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Fig. 1

Illustration of the experimental setup in the tunnel test section including coordinate systems used

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Fig. 2

Mean velocity profiles measured at different inflow conditions. The shown profiles are relative to the configurations: (a) plain, (b) spires, no hills, (c) hills, and (d) hills and spires. (Dotted lines) U = 5 m/s, (solid lines) U = 7.5 m/s, and (dashed lines) U = 10 m/s. The error bars indicate the spanwise variability for U = 7.5 m/s and the gray shaded areas mark the region spanned by the turbine-rotors. The ratio of the turbine-rotor diameter to the tunnel height D/H = 0.15.

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Fig. 3

Normalized velocity standard deviation measured at different inflow conditions. The shown profiles are relative to the configurations: (a) plain, (b) spires, no hills, (c) hills, and (d) hills and spires. (Dotted lines) U = 5 m/s, (solid lines) U = 7.5 m/s, and (dashed lines) U = 10 m/s. The error bars indicate the spanwise variability for U = 7.5 m/s and the gray shaded areas mark the region spanned by the turbine-rotors. The ratio of the turbine-rotor diameter to the tunnel height D/H = 0.15.

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Fig. 4

Picture of experimental equipments used in the tunnel test section including spires, grids, and hot-wire traversing system

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Fig. 5

Front-row turbine power coefficients with different back-row turbine positions. The solid line indicates the mean CP value and the dashed lines indicate a variability in CP of ± 1%.

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Fig. 6

Illustration of the wind-turbine positions with a spanwise spacing Δy = R

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Fig. 7

Performance of the single turbine with all test-section configurations: (a) power coefficient and (b) thrust coefficient at varying tip-speed ratio λ

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Fig. 8

Turbine performance with the plain configuration: (a) power coefficient and (b) thrust coefficient at varying tip-speed ratio λ

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Fig. 9

Turbine performance for the configuration with hills: (a) power coefficient and (b) thrust coefficient at varying tip-speed ratio λ

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Fig. 10

Turbine performance for the configuration with hills and spires: (a) power coefficient and (b) thrust coefficient at varying tip-speed ratio λ

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Fig. 11

Mean velocity profiles in the wake of a single turbine placed at X*/D = −4. The profiles are captured along the tunnel centerline (Y*/D = 0) at X*/D = −1.6 (a), X*/D = −1.1 (b), X*/D = −0.5 (c), and X*/D = 0 (d). The origin of the vertical coordinate Z*/D is at the turbine hub-height for the different flow configurations plain (solid lines), hills (dashed lines), and hills + spires (dotted lines). The downstream turbine was not present during these measurements.

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Fig. 12

Turbine performance with all test-section configurations for Δy = 0: (a) power coefficient and (b) thrust coefficient at varying tip-speed ratio λ

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Fig. 13

Mean velocity profiles in wake of two aligned turbines (Δy = 0) placed at X*/D = −4 and X*/D = 0. The profiles are captured along the tunnel centerline (Y*/D = 0) at the streamwise coordinates X*/D = 0.5 (a), X*/D = 1.1 (b), X*/D = 1.6 (c), and X*/D = 2.1 (d). The origin of the vertical coordinate Z*/D is at the turbine hub-height for the different flow configurations plain (solid lines), hills (dashed lines), and hills + spires (dotted lines).

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Fig. 14

Turbine performance in all test-section configurations for Δy = R: (a) power coefficients and (b) thrust coefficients at varying tip-speed ratio λ

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