Experimental Studies Of Anemometers

Author : Yng-Ru Chen
Publisher :
ISBN 13 :
Total Pages : 123 pages
Book Rating : 4.:/5 (958 download)

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Download or read book Characterization of Cup Anemometer Dynamics and Calculation of the Acoustic Noise Produced by a NREL Phase VI Wind Turbine Blade written by Yng-Ru Chen and published by . This book was released on 2015 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt: The results of two separate investigations into two issues related to the generation of electrical power from wind are reported in this dissertation. The first, an experimental investigation of cup anemometer dynamics, is motivated by the need to accurately measure local wind conditions at wind turbine array locations. This need is two-fold, one being the need to assess wind-turbine performance (in terms of the conversion of wind power to electrical power, the second is to ensure that predictions of the wind power capacity of a given area of interest are based on reliable wind speed measurements. The purpose of the investigation is to shed light on possible approaches to mitigate potential shortcomings of wind data collected using cup anemometers by a systematic experimental investigation of their performance under simulated “gusts” in a wind tunnel. It is found that the response of the anemometer to changing wind conditions is determined by two parameters both of which represent the ratio of drag forces to inertial forces. In the recent of a sudden decrease in wind speed to zero, one of the parameters alone controls the rate of decay of the anemometers speed to zero. This parameter is measured experimentally for 4 different anemometers at three different initial wind speeds The second part of this dissertation deals with the subject of aeroacoustic noise. An important factor to take into consideration in the development of wind farms near populated areas is the potential for noise disturbance. In this dissertation, the topic of aeroacoustic noise is addressed using a computational fluid dynamic model to compute the wind velocity and pressure fields through the turbine. The Ffowcs-Williams and Hawkings acoustic analogy is used to calculate the acoustic pressure at a far field receiver location. The results obtained are compared with experimental data. The purpose of the investigation is, by extending earlier work of Ranft et al., to predict the aeroacoustic noise at different wind speeds and at different rotational speeds of the turbine. Both rotational noise and broadband noise were analyzed. It was found that the leading edge and the blade tip are the primary source of the broadband noise. In all simulations, the loudest noise (80.8 dB) generated by the wind turbine blade tip and the leading edge are higher than the World Health Organization recommended noise level standards but decay with increasing distance from the turbine.