Potential negative effects of wind turbines on the ear
Duvvury, Rolan Shawn
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This thesis presents investigations on the potential negative effects of wind turbine noise on the human ear from a sound point source (i.e. wind farm). In Chapter 2, the tectorial membrane, which is a crucial gelatinous structural matrix located within the cochlea of the inner ear, is considered to have a similar constitutive stress-strain relationship to that of an elastomer (rubber) in tension. The tectorial membrane appears to stretch when subjected to constant heavy sound stimulation. The tectorial membrane is modeled as a simply-supported beam with an external load Pext applied at midspan. A virtual work approach is used to balance the external work at midspan Pextδz of the tectorial membrane with the internal strain energy from its hysteresis loops. These hysteresis loops quantify the amount of damage that the tectorial membrane undergoes due to an applied external loading. Normalized damage tables are presented at the end of the chapter to suggest safe distances away from the wind turbines to limit damage to the tectorial membrane. Chapter 3 considers a hypothetical autonomous village constructed in South Pretoria, South Africa. This village accommodates approximately 2000 people (~500 families) and receives electricity for hot water from a nearby 2.5 MW wind farm. The design process for the village is discussed from an architectural and design standpoint. The wind farm specifications, specifically the number of 2.5 MW wind turbines needed to provide electricity for hot water, are established. Results from Chapter 2 are used to suggest minimum safe distances between the wind farm and the autonomous village in the context of limiting damage to the tectorial membrane.