Eventos Anais de eventos
ENCIT 2020
18th Brazilian Congress of Thermal Sciences and Engineering
ASSESSMENT OF MACH NUMBER EFFECTS ON SECONDARY TONES ARISING IN AIRFOIL FLOWS
Submission Author:
Tulio Rodarte Ricciardi , SP
Co-Authors:
Tulio Rodarte Ricciardi, William Wolf
Presenter: Tulio Rodarte Ricciardi
doi://10.26678/ABCM.ENCIT2020.CIT20-0119
Abstract
Direct numerical simulations are carried out to investigate the flow features responsible for secondary tones in airfoil noise at Reynolds number $Re_c=5\times10^4$. Results show that noise emissions have a main tone with equidistant secondary tones, as discussed in literature. Flow simulations of a NACA 0012 airfoil are conducted for freestream Mach numbers ranging from 0.2 to 0.4 at 3 deg. angle of incidence. Initial findings show that a low-frequency modulation of the vortex dynamics induces phase variation of flow instabilities developed along the airfoil boundary layer. The modulation directly affects the velocity and pressure fluctuations that are scattered at the trailing edge, resulting in acoustic radiation of secondary tones.
Keywords
Aeroacoustics, vortex dynamics, Frequency modulation
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