Linear Stability Theory applied in a croos-stream profile of a shear layer of leading edge slat cove

Himeno, Fernando H T¹; Amaral, F R¹; Medeiros, Marcello A F¹

¹ University of Sao Paulo, Sao Carlos

doi:10.20906/CPS/CILAMCE2017-0344

Resumo

Aircraft noise has been a topic of interest in aeronautics since 70s. A large portion of noise was reduced with the inclusion of turbofan engines and then intense efforts were dedicated to the reduction of airframe noise in which high-lift surfaces represent one of the most critical sources. Leading edge slat, employed in a large part of the air fleet in most of the large aircrafts, is a high-lift system distributed over the whole wing span and this increases its importance in noise studies. The shear layer flow in the slat cove is very turbulent and is the source of the slat noise. In order to understand the shear layer features and fluctuations related to structures that could be related to sources of noise, a numerical study is presented. Linear Stability Theory was applied to the mean flow of the slat cove shear layer. Cross-stream profiles were approximated to hyperbolic tangent functions. Results of most unstable frequencies and amplitudes of fluctuation velocity along the shear layer shows good agreement with experimental data.

Palavras-chave: Aeroanautics; Aeroacoustics; Slat; LST