Flow topology and acoustic emissions of trailing edge serrations at incidence

Journal article (2016)

Authors

C.A. Arce Leon Aerodynamics - Aerospace Engineering
D. Ragni Wind Energy - Aerospace Engineering
S. Pröbsting Wind Energy - Aerospace Engineering
F. Scarano Flow Physics and Technology
Jesper Madsen Aerodynamics and Acoustics Group
Research Group
Aerodynamics (Aerospace Engineering) (TU Delft)
Copyright: © 2016 C.A. Arce Leon, D. Ragni, S. Pröbsting, F. Scarano, Jesper Madsen
DOI
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https://doi.org/10.1007/s00348-016-2181-1
Aeroacoustics Particle image velocimetry Edges Serrated trailing
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Published Date

2016

Language

English

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Faculty

Aerospace Engineering

Department

Flow Physics and Technology

Research Group

Aerodynamics

Abstract

The flow past a NACA 0018 airfoil with sawtooth trailing edge serrations has been investigated using stereoscopic particle image velocimetry (PIV). The serration flap angle and airfoil incidence are varied in order to study the effect of secondary flow establishing between the suction and pressure sides of the serrations. The flow topology around the serrations is inferred from the analysis of time-averaged streamlines close to the airfoil surface and from the wall-normal flow velocity in between serrations. Additional PIV measurements with a plane in cross-flow highlight the formation of streamwise vortex pairs. The flow behavior is further characterized in terms of its turbulence statistics. Noise emissions are measured with an acoustic phased array in combination with beamforming. The serrations are found to be effective in reducing noise, and their application is studied for different degrees of airfoil incidence and serration flap angle.