TY - JOUR
T1 - Coupled structural resonance of elastic panels for suppression of airfoil tonal noise
AU - Arif, Irsalan
AU - Lam, Garret C.Y.
AU - Leung, Randolph C.K.
N1 - Funding Information:
The authors gratefully acknowledge the support from a research donation from the Philip K. H. Wong Foundation, Hong Kong, China under grant number 5-ZH1X. The first author gratefully acknowledges the support with research studentship tenable at Department of Mechanical Engineering, The Hong Kong Polytechnic University (PolyU). The second and third authors are grateful to the support from the Research Grants Council of the Government of Hong Kong Special Administrative Region under grant number A-PolyU 503/15 and the ANR/RGC International FlowMatAc number ANR-15-CE22-0016-01. The provision of computer times by University Research Facility in Big Data Analytics (UBDA) at PolyU is much appreciated.
Funding Information:
The authors gratefully acknowledge the support from a research donation from the Philip K. H. Wong Foundation, Hong Kong, China under grant number 5-ZH1X . The first author gratefully acknowledges the support with research studentship tenable at Department of Mechanical Engineering, The Hong Kong Polytechnic University (PolyU) . The second and third authors are grateful to the support from the Research Grants Council of the Government of Hong Kong Special Administrative Region under grant number A-PolyU 503/15 and the ANR/RGC International FlowMatAc number ANR-15-CE22-0016-01 . The provision of computer times by University Research Facility in Big Data Analytics (UBDA) at PolyU is much appreciated.
Publisher Copyright:
© 2022 Elsevier Ltd
PY - 2022/4
Y1 - 2022/4
N2 - In this paper the aeroacoustic characteristics of coupled flow-induced vibration of elastic panels mounted on an airfoil is numerically studied to uncover its potential for suppression of airfoil tonal noise. The proposed approach utilizes the inter-dynamical structural coupling between two elastic panels which maintain a synchronized flow-induced vibration pattern to weaken the flow fluctuations responsible for tonal noise generation. In the study, a NACA0012 airfoil at a low Reynolds number of 5×104 and an angle of attack of 5° is taken as the basic structure on which various panel configurations are attempted. The results of preliminary analysis of aeroacoustic-structural interactions of various panel configurations, using a reduced-order modeling approach, reveal that an airfoil-panel configuration with two elastic panels separated by approximately one convective wavelength and mounted in a region exposed to high boundary layer flow instabilities yields optimal noise suppression. Comprehensive aerodynamic and acoustic analyzes of airfoil-panel configurations, using the results of high fidelity direct aeroacoustic simulation, reveal that an average and maximum noise suppression up to 7.6 dB and 7.9 dB respectively can be achieved with negligible sacrifice on overall airfoil aerodynamics when strongly coupled structural resonance between the panels prevails. The magnitude of noise suppression is higher than twice of that from the configuration mounted with a single panel. This fact firmly illustrates the synergy of coupled flow-induced structural resonance of the panels prevailing in noise suppression. Nonlinear fluid–structure interactions of coupled resonant panels in airfoil-panel configuration are characterized by extensive spectral analyzes in frequency and wavenumber domains as well as correlation analyzes. The panels exhibit highly synchronized dynamic behaviors and run into limit cycle oscillations. Their strongly coherent structural responses are proven able to provide a more effective suppression of the boundary layer instabilities to be scattered at airfoil trailing edge as noise. The upstream propagating component of the generated noise does not interfere the coupled structural resonance of the panels as revealed from their weak correlations. Key characteristics required for the design of strongly coupled structural resonant panels for effective absorption of flow fluctuation energy are discerned and discussed.
AB - In this paper the aeroacoustic characteristics of coupled flow-induced vibration of elastic panels mounted on an airfoil is numerically studied to uncover its potential for suppression of airfoil tonal noise. The proposed approach utilizes the inter-dynamical structural coupling between two elastic panels which maintain a synchronized flow-induced vibration pattern to weaken the flow fluctuations responsible for tonal noise generation. In the study, a NACA0012 airfoil at a low Reynolds number of 5×104 and an angle of attack of 5° is taken as the basic structure on which various panel configurations are attempted. The results of preliminary analysis of aeroacoustic-structural interactions of various panel configurations, using a reduced-order modeling approach, reveal that an airfoil-panel configuration with two elastic panels separated by approximately one convective wavelength and mounted in a region exposed to high boundary layer flow instabilities yields optimal noise suppression. Comprehensive aerodynamic and acoustic analyzes of airfoil-panel configurations, using the results of high fidelity direct aeroacoustic simulation, reveal that an average and maximum noise suppression up to 7.6 dB and 7.9 dB respectively can be achieved with negligible sacrifice on overall airfoil aerodynamics when strongly coupled structural resonance between the panels prevails. The magnitude of noise suppression is higher than twice of that from the configuration mounted with a single panel. This fact firmly illustrates the synergy of coupled flow-induced structural resonance of the panels prevailing in noise suppression. Nonlinear fluid–structure interactions of coupled resonant panels in airfoil-panel configuration are characterized by extensive spectral analyzes in frequency and wavenumber domains as well as correlation analyzes. The panels exhibit highly synchronized dynamic behaviors and run into limit cycle oscillations. Their strongly coherent structural responses are proven able to provide a more effective suppression of the boundary layer instabilities to be scattered at airfoil trailing edge as noise. The upstream propagating component of the generated noise does not interfere the coupled structural resonance of the panels as revealed from their weak correlations. Key characteristics required for the design of strongly coupled structural resonant panels for effective absorption of flow fluctuation energy are discerned and discussed.
KW - Aeroacoustic-structural interaction
KW - Airfoil self-noise
KW - Conservation element and solution element scheme
KW - Flow-induced vibration
KW - Perturbation evolution method
UR - http://www.scopus.com/inward/record.url?scp=85124622634&partnerID=8YFLogxK
U2 - 10.1016/j.jfluidstructs.2022.103506
DO - 10.1016/j.jfluidstructs.2022.103506
M3 - Journal article
AN - SCOPUS:85124622634
SN - 0889-9746
VL - 110
JO - Journal of Fluids and Structures
JF - Journal of Fluids and Structures
M1 - 103506
ER -