A Practical Method for Estimating a Presence of a Prominent Tonal Component in Wind Turbine Noise

In order to take a survey of a presence of tonal component(s) contained in wind turbine noise in a field measurement, authors have been investigating a practical method for estimation of the Tonal Audibility (TA) using not a dedicated TA analyzer but a FFT or 1/N octave band analyzer. Based on a principle of determination of the TA, an estimation method for a tonal component by applying FFT analysis with no classification of each spectral line of the spectrum around a tonal component is proposed. From a viewpoint of an environmental noise measurement, 1/N octave band analysis (especially 1/3 octave band) is important, therefore, a method for a prominent tonal component applying 1/N octave band analysis is examined including the survey method specified in ISO 1996-2:2017. The proposed methods based on FFT analysis and 1/N octave band analysis are examined by comparing the relationship between the calculated TAs and the estimated results for a model noise including a tonal component. The TA where a tonal component in wind turbine noise is evaluated as prominent is also compared with the results of subjective experiments on audibility of a tonal component in wind turbine noise.