| Budget Amount *help |
¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000)
Fiscal Year 2017: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2016: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2015: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000)
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| Outline of Final Research Achievements |
Wind turbine noise generally has the amplitude modulation components which often cause psychological annoyance in residential areas around wind farms. To examine the characteristics of amplitude modulated sound generated from a single wind turbine, field measurements have been performed under various wind conditions. The method for extracting the amplitude modulation components from the analyzed sound pressure levels was proposed. The distinguishable directivity of the amplitude modulation contained in wind turbine noise was revealed, whose pattern tended to be highest in the directions of approximately 60 degrees relative to the nacelle. In addition, the strength distributions of the amplitude modulation at distances of up to 200 m were examined. Almost all the strengths of the amplitude modulation component still remained 2 dB or more at distances of even a few hundred meters, whereas the A-weighted sound pressure levels decreased with increasing propagation distance.
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