Experimental study on effect of surface roughness on output power of wind turbines
Four boundary layers conforming to different wind contour indices were constructed using a combination of sharp splits and rough elements.Only the effect of different wind profiles on the wind turbine power spectrum was investigated,under the premise that the mean wind speed of the incoming flow at the hub height,the turbulence integration scale,and the wind pulsation power spectrum were satisfied to be the same.The results show that the wind turbine output power spectrum and the turbulence spectrum of the incoming flow behave as three corresponding regions in the frequency domain,which are the low-frequency region of the turbulence spectrum represented by large scale turbulent structures,the intermediate region represented by turbulent energy dissipation,the intermediate region representing turbulent energy dissipation,and the high-frequency region represented by small and microscale eddies.It is found that under different surface roughness,the wind turbine output power spectra corresponding to the intermediate region show different slopes of attenuation,and under the same surface roughness,the degree of attenuation is independent of the turbulence integral scale,wind speed and other factors,and the spectral characteristics of the two quantities show a nonlinear relationship,and the slope of the attenuation has a tendency to increase with the increase of the surface roughness.The output power of the wind turbine varies greatly under different wind profile indices,and the energy difference in the incoming flow is found to be an important reason for the variation of the output power.
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