Eventos Anais de eventos
ENCIT 2018
Brazilian Congress of Thermal Sciences and Engineering
A NUMERICAL INVESTIGATION OF ANGLE OF ATTACK EFFECTS ON AIRFOIL NOISE SECONDARY TONES
Submission Author:
Lucas Frederico , SP
Co-Authors:
Lucas Frederico, William Wolf
Presenter: William Wolf
doi://10.26678/ABCM.ENCIT2018.CIT18-0811
Abstract
Numerical simulations of a NACA0012 airfoil under moderate Reynolds number conditions (50.000 < Re < 100.000) are carried out in order to assess the noise generation phenomena (broadband + tonal noise) including the flow structures along the boundary layer. We employ a computational fluid dynamics tool with low dispersion and dissipation characteristics, able to resolve unsteady flow features which may occur in the mentioned conditions, such as the unsteady disturbances that appear on the airfoil surface (Tollmien-Schlichting waves) and which are amplified via an acoustic feedback mechanism near the trailing edge. This mechanism makes the shear layer highly unstable close to the trailing edge and is believed to be the cause of secondary tones observed in the noise spectra. In order to examine aspects of the flow stability and its spatial characteristics, techniques such as Fourier transform, wavelet transforms and dynamic mode decomposition are applied.
Keywords
Airfoil trailing-edge noise, trailing-edge instability, dynamic mode decomposition
