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Directivity of blade-tower interaction noise.
Yendrew Yauwenas1, Branko Zajamšek2, John Reizes1
1School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, New South Wales 2035, Australia.
JASA Express Letters
|September 26, 2022
Summary
This study characterizes wind turbine blade-tower interaction (BTI) noise directivity. Combining computational fluid dynamics and acoustic analogy, researchers found BTI noise exhibits an oval pattern due to blade and tower noise interference.
Area of Science:
- Acoustics
- Aerodynamics
- Computational Fluid Dynamics (CFD)
Background:
- Blade-tower interaction (BTI) is a significant noise source in wind turbines.
- Understanding BTI noise directivity is crucial for noise mitigation strategies.
- Previous studies have not fully characterized the combined directivity patterns of blade and tower noise components.
Purpose of the Study:
- To characterize the directivity of blade-tower interaction (BTI) noise.
- To investigate the individual noise contributions of turbine blades and the tower.
- To analyze the combined noise directivity pattern resulting from BTI.
Main Methods:
- Employed a hybrid numerical approach combining unsteady Reynolds-averaged Navier-Stokes (URANS) equations with Curle's acoustic analogy.
- Computed noise generated by the blades and the tower separately.
- Analyzed the directivity patterns of individual noise sources and their combined effect.
Main Results:
- Blade noise directivity exhibits a dipole pattern.
- Tower noise directivity shows a monopole-like pattern.
- The combined BTI noise directivity results in an oval-shaped pattern, influenced by partial cancellations between blade and tower noise components.
Conclusions:
- The directivity of wind turbine noise is significantly shaped by blade-tower interactions.
- The distinct dipole and monopole-like patterns of blade and tower noise, respectively, combine to form an oval directivity.
- Partial cancellations between noise sources play a key role in determining the overall BTI noise directivity.
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