Effect of Bubble Seal on Slat Noise

Author(s)

do Amaral, Filipe Ramos ^[1] ; Tadashi Himeno, Fernando Henrique ^[1] ; Souza, Daniel Sampaio ^{[2, 3]} ; Pagani Junior, Carlos do Carmo ^[2] ; Faraco de Medeiros, Marcello Augusto ^[4]

Affiliation

^[1] Univ Sao Paulo, Dept Mech Engn, BR-13566590 Sao Carlos, SP - Brazil

^[2] Sao Paulo State Univ, Campus Sao Joao Da Boa Vista, BR-13876750 Sao Joao Da Boa Vista - Brazil

^[3] Univ Fed Sao Joao del Rei, Dept Thermal & Fluid Sci, BR-36307352 Sao Joao Del Rei, MG - Brazil

^[4] Univ Sao Paulo, Dept Aeronaut Engn, BR-13566590 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: AIAA JOURNAL; v. 57, n. 4, p. 1608-1623, APR 2019.
• Web of Science Citations: 1

Abstract

This paper reports a study of the sound emitted by a slat of a two-dimensional three-element MD30P30N airfoil, on which a two-dimensional excrescence was installed to represent a sealing device. Experiments were conducted in a closed-test-section wind-tunnel, and a conventional beamforming technique combined with DAMAS deconvolution method was employed for the evaluation of the radiated noise. Nine seal positions along the slat cove wall and six different seal cross sections were tested for 3-9 deg angles of attack and 34 m/s freestream speed. Mean static pressure measurements on the airfoil surface indicated that the seals did not impact the airfoil lift but significantly affected the slat noise signature, particularly the low-frequency narrowband peaks. At some positions, the narrowband peaks were increased up to 18 dB/Hz, whereas for other positions, they were virtually suppressed. At the noisiest position, even a seal whose height was 1.33% of the slat chord strongly affected the slat noise signature. Lattice Boltzmann numerical simulations in combination with the Ffowc Williams-Hawkings analogy were conducted for experimental cases selected and revealed the strong effect of the seal on the mean flow and the turbulence recirculation in the slat cove. (AU)

• FAPESP's process: 06/52568-7 - Silent aircraft: a research on aeronautics
• Grantee: Julio Romano Meneghini
• Support Opportunities: Research Grants - Research Partnership for Technological Innovation - PITE
• FAPESP's process: 16/02970-5 - Computational study of aeroacoustic effect of a seal located on slat cove and analysis by POD technique
• Grantee: Fernando Henrique Tadashi Himeno
• Support Opportunities: Scholarships in Brazil - Master