Torque fluctuations caused by upstream mean flow and turbulence

The Science of Making Torque from Wind 2012

Farr, T.D.^1 ; Hancock, P.E.^1

EnFlo Laboratory, University of Surrey, Guildford, United Kingdom^1

关键词: Cross correlations;    Current sensors;    Motor generator;    Stream-wise velocities;    Torque fluctuation;    Turbulent motion;    Upstream velocity;    Wake interactions;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/555/1/012048/pdf
DOI  :  10.1088/1742-6596/555/1/012048

来源: IOP

【 摘 要 】

A series of studies are in progress investigating the effects of turbine-array-wake interactions for a range of atmospheric boundary layer states by means of the EnFlo meteorological wind tunnel. The small, three-blade model wind turbines drive 4-quadrant motor-generators. Only a single turbine in neutral flow is considered here. The motor-generator current can be measured with adequate sensitivity by means of a current sensor allowing the mean and fluctuating torque to be inferred. Spectra of torque fluctuations and streamwise velocity fluctuations ahead of the rotor, between 0.1 and 2 diameters, show that only the large-scale turbulent motions contribute significantly to the torque fluctuations. Time-lagged cross-correlation between upstream velocity and torque fluctuations are largest over the inner part of the blade. They also show the turbulence to be frozen in behaviour over the 2 diameters upstream of the turbine.