Numerical Investigations of Bio-Inspired Blade Designs to Reduce Broadband Noise in Aircraft Engines and Wind Turbines

Abstract

<p>Simplified representations of the leading edge serrations in owl feathers are modeled numerically to investigate their effectiveness in reducing inflow turbulence noise. The rod wake-airfoil interaction problem is selected for this investigation. Two numerical methods utilizing compressible- and incompressible large eddy simulation techniques are used for the analyses. The methods are first validated against experimental results for the baseline airfoil (no serrations). Good agreement is observed between measurement and predictions for mean surface pressure, near-field velocity spectra, and far-field sound spectra. Two serrated leading edge blade designs are then analyzed for noise. The leading edge serrations are found to give a noise reduction of up to 5 decibels in the mid-to-high frequency range.</p>