Vibrations in Physical Systems Vol.26 (2014) Infrasound and Low Frequency Noise of a Wind TurBine Malgorzata WOJSZNIS Institute of Applied Mechanics, Poznan University of Technology 3 Piotrowo Street, 60-965 Poznań
[email protected] Jacek SZULCZYK Environmental Acoustics Laboratory EKO – POMIAR 4 Sloneczna Street, 64-600 Oborniki
[email protected] ABstract The paper presents noise evaluation for a 2 MW wind turbine. The obtained results have been analyzed with regard to infrasound and low frequency noise generated during work of the wind turbine. The evaluation was based on standards and decrees binding in Poland. The paper presents also current literature data on the influ- ence of the infrasound and low frequency noise on a human being. It has been concluded, that the permissible levels of infrasound for the investigated wind turbine were not exceeded. Keywords: low frequency noise, infrasound, wind turbine 1. Introduction Research that has been conducted in the world for many years shows that noise can be described as sound below and above so called hearing threshold . It can be assumed that the infrasound , which cannot be heard by a human being, concerns frequencies below 20 Hz, and the ultrasound concerns frequencies above 20 kHz [1]. We receive it as me- chanical vibrations of the medium it passes through, transferring energy from the source in the form of acoustic waves. Puzyna in [1] describes infrasound as infraaccoustic vi- brations . Some investigations show that for some people the hearing level begins already at 16Hz, and sometimes even at 4Hz. Such a phenomenon occurs at appropriate condi- tions and at a high level of sound pressure [2].