TY - JOUR
T1 - Wake and power fluctuations of a model wind turbine subjected to pitch and roll oscillations
AU - Fu, Shifeng
AU - Jin, Yaqing
AU - Zheng, Yuan
AU - Chamorro, Leonardo P.
N1 - Funding Information:
This material is based upon work supported by the National Science Foundation under Grant No. ECCS-041544081 . This work was also supported by Mech. Sci. and Eng. Dept, U. of Illinois, as part of the start-up package of L. P. C., the Fundamental Research Funds for the Central Universities (Grant No. 2017B687X14 ) and Postgraduate Research & Practice Innovation Program of Jiangsu Province (Grant No. KYCX17_0430 ). S.F. was also supported by the National Natural Science Fund (Grant No. 51579080 ) and Natural Science Found of Anhui Province (Grant No. 1608085ME119 ).
Funding Information:
This material is based upon work supported by the National Science Foundation under Grant No. ECCS-041544081. This work was also supported by Mech. Sci. and Eng. Dept, U. of Illinois, as part of the start-up package of L. P. C. the Fundamental Research Funds for the Central Universities (Grant No. 2017B687X14) and Postgraduate Research & Practice Innovation Program of Jiangsu Province (Grant No. KYCX17_0430). S.F. was also supported by the National Natural Science Fund (Grant No. 51579080) and Natural Science Found of Anhui Province (Grant No. 1608085ME119).
Publisher Copyright:
© 2019 Elsevier Ltd
PY - 2019/11/1
Y1 - 2019/11/1
N2 - Wind-tunnel experiments were performed to inspect the impact of a variety of pitch and roll oscillations of a model wind turbine on the instantaneous power output and wake. Particle image velocimetry and hotwire anemometry were used to characterize the flow in the wake; instantaneous power output was also obtained in each of the configurations. For comparison, measurements were also performed in a fixed wind turbine. Results show that the wake at the turbine symmetry plane is significantly altered by the imposed motions, where rolling induced the lowest momentum deficit. The mean power output of the turbine increased with moderate tower oscillations, namely ≲10°, independent of the type of motion. We argue that this is due to, at least, two distinctive processes. Namely, a relative gain due to the cube of the relative incoming velocity impinging the rotor in the pitching, and a momentum replenish in the rolling motion The power fluctuations exhibited a peak on the spectral content of the spectrum ΦP coincident with the frequencies of the pitching and rolling. They also revealed the effects of the oscillation within the low-frequency content of ΦP, which was likely due to the oscillation-driven changes in the aerodynamics of the blades. In particular, the pitch reduced the energy of the power fluctuations within frequencies below that of the pitching frequency, with stronger effect at larger amplitude of oscillations, θ. However, the roll motions reduced the energy of the power fluctuations in a relatively narrow band, and notorious only with θ≳10°.
AB - Wind-tunnel experiments were performed to inspect the impact of a variety of pitch and roll oscillations of a model wind turbine on the instantaneous power output and wake. Particle image velocimetry and hotwire anemometry were used to characterize the flow in the wake; instantaneous power output was also obtained in each of the configurations. For comparison, measurements were also performed in a fixed wind turbine. Results show that the wake at the turbine symmetry plane is significantly altered by the imposed motions, where rolling induced the lowest momentum deficit. The mean power output of the turbine increased with moderate tower oscillations, namely ≲10°, independent of the type of motion. We argue that this is due to, at least, two distinctive processes. Namely, a relative gain due to the cube of the relative incoming velocity impinging the rotor in the pitching, and a momentum replenish in the rolling motion The power fluctuations exhibited a peak on the spectral content of the spectrum ΦP coincident with the frequencies of the pitching and rolling. They also revealed the effects of the oscillation within the low-frequency content of ΦP, which was likely due to the oscillation-driven changes in the aerodynamics of the blades. In particular, the pitch reduced the energy of the power fluctuations within frequencies below that of the pitching frequency, with stronger effect at larger amplitude of oscillations, θ. However, the roll motions reduced the energy of the power fluctuations in a relatively narrow band, and notorious only with θ≳10°.
KW - Pitch and roll motions
KW - Power output fluctuations
KW - Turbine oscillations
KW - Turbine wake
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U2 - 10.1016/j.apenergy.2019.113605
DO - 10.1016/j.apenergy.2019.113605
M3 - Article
AN - SCOPUS:85069912488
SN - 0306-2619
VL - 253
JO - Applied Energy
JF - Applied Energy
M1 - 113605
ER -