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Aeroacoustic Characterization of a Multi-Element High-Lift Airfoil

Title: An Aeroacoustic Characterization of a Multi-Element High-Lift Airfoil.
Name(s): Pascioni, Kyle A., author
Cattafesta, Louis N., professor directing dissertation
Sussman, Mark, university representative
Alvi, Farrukh S., committee member
Xu, Cheryl, committee member
Choudhari, Meelan, 1963-, committee member
Florida State University, degree granting institution
College of Engineering, degree granting college
Department of Mechanical Engineering , degree granting department
Type of Resource: text
Genre: Text
Doctoral Thesis
Issuance: monographic
Date Issued: 2017
Publisher: Florida State University
Florida State University
Place of Publication: Tallahassee, Florida
Physical Form: computer
online resource
Extent: 1 online resource (283 pages)
Language(s): English
Abstract/Description: The leading edge slat of a high-lift system is known to be a large contributor to the overall radiated acoustic field from an aircraft during the approach phase of the flight path. This is due to the unsteady flow field generated in the slat-cove and near the leading edge of the main element. In an effort to understand the characteristics of the flow-induced source mechanisms, a suite of experimental measurements has been performed on a two-dimensional multi-element airfoil, namely, the MD-30P30N. Particle image velocimetry provide mean flow field and turbulence statistics to illustrate the differences associated with a change in angle of attack. Phase-averaged quantities prove shear layer instabilities to be linked to narrowband peaks found in the acoustic spectrum. Unsteady surface pressure are also acquired, displaying strong narrowband peaks and large spanwise coherence at low angles of attack, whereas the spectrum becomes predominately broadband at high angles. Nonlinear frequency interaction is found to occur at low angles of attack, while being negligible at high angles. To localize and quantify the noise sources, phased microphone array measurements are per- formed on the two dimensional high-lift configuration. A Kevlar wall test section is utilized to allow the mean aerodynamic flow field to approach distributions similar to a free-air configuration, while still capable of measuring the far field acoustic signature. However, the inclusion of elastic porous sidewalls alters both aerodynamic and acoustic characteristics. Such effects are considered and accounted for. Integrated spectra from Delay and Sum and DAMAS beamforming effectively suppress background facility noise and additional noise generated at the tunnel wall/airfoil junction. Finally, temporally-resolved estimates of a low-dimensional representation of the velocity vector fields are obtained through the use of proper orthogonal decomposition and spectral linear stochastic estimation. An estimate of the pressure field is then extracted by Poissons equation. From this, Curles analogy projects the time-resolved pressure forces on the airfoil surface to further establish the connection between the dominating unsteady flow structures and the propagated noise.
Identifier: FSU_2017SP_Pascioni_fsu_0071E_13776 (IID)
Submitted Note: A Dissertation submitted to the Department of Mechanical Engineering in partial fulfillment of the requirements for the degree of Doctor of Philosophy.
Degree Awarded: Spring Semester 2017.
Date of Defense: March 30, 2017.
Keywords: 30P30N, Aeroacoustics, High-Lift, Kevlar, Slat Noise, Wind Tunnel
Bibliography Note: Includes bibliographical references.
Advisory Committee: Louis Cattafesta, Professor Directing Dissertation; Mark Sussman, University Representative; Farrukh Alvi, Committee Member; Chengying Xu, Committee Member; Meelan Choudhari, Committee Member.
Subject(s): Aerospace engineering
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Host Institution: FSU

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Pascioni, K. A. (2017). An Aeroacoustic Characterization of a Multi-Element High-Lift Airfoil. Retrieved from