Acoustic radiation of subsonic jets at the vicinity of an inclined flat plate

Resumo

© 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.A study of the influence of the incidence angle in the acoustics of installed jets is presented here. Acoustic measurements of turbulent jets in the vicinity of a _at plate, mimicking a neighbouring wing, were compared to results from two models previously studied in the literature, both based on a wavepacket source: the Tailored Green's Function method, which considers the radiation of the turbulent structure in the vicinity of a semi-infinite flat plate, and the Boundary Element Method, which can represent the full geometry of the plate used in the experiments. Particular interest is given to analysing how the angle of attack of the plate affects the sound radiated by this installed jet configuration. The results herein confirm the behaviour identified by the said models: the scattered acoustic field follows the rotation of the plate, shifting the silence region and creating regions with lower noise levels in positions that, for an aircraft with engines under its wings, correspond to the ground. The robustness of this phenomenon is assessed by means of a Mach number analysis with the experimental approach, showing that this trend is present whenever the acoustic scattering is dominant.