Numerical computation of aeroacoustic transfer functions for realistic airfoils

Miotto, Renato F.; Wolf, William; Santana, Leandro D. de

doi:10.1016/j.jsv.2017.06.037

Cited by 13 publications

(21 citation statements)

References 36 publications

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“…However, they also observed that, at moderate Mach numbers (M 0 0.6), the blunter leading edge could increase farfield noise in the upstream direction for high-frequency gusts. Such a trend has been also observed in [13,18,25].…”

Section: Rapid Distortion Theorysupporting

confidence: 69%

“…However, the aeroacoustic transfer function presents noteworthy differences for thick airfoil profiles. For example, recent research [13] shows that the airfoil thickness reduces the magnitude of the unsteady pressure distribution along the airfoil surface reducing, therefore, the magnitude of the aeroacoustic transfer function.…”

Section: A Acoustic Radiation: Amiet's Theorymentioning

confidence: 99%

“…The BEM approach proposed in [13] allows the calculation of the aeroacoustic transfer function accounting for general airfoil profiles. The proposed approach numerically solves the boundary value problem prescribed by the linearized airfoil theory in the transformed Prandtl-Glauert plane, providing the unsteady load distribution over the airfoil surface.…”

Section: B Aeroacoustic Transfer Function For General Airfoil Profilesmentioning

confidence: 99%

“…Recently, Miotto et al [13] developed a boundary element method (BEM) for computing the aeroacoustic transfer function in the gustairfoil interaction problem. The proposed methodology allowed a study of the leading-edge noise produced due to an incident turbulent inflow interacting with general airfoil profiles, three-dimensional supercritical perturbations, and compressible subsonic flows.…”

Section: Introductionmentioning

confidence: 99%

“…The proposed methodology allowed a study of the leading-edge noise produced due to an incident turbulent inflow interacting with general airfoil profiles, three-dimensional supercritical perturbations, and compressible subsonic flows. The current work proposes to combine the technique described in [13] with the inverse strip method presented by Christophe et al [14] to predict the leading-edge noise from general airfoil profiles with spanwise-varying inflow conditions. In this research, a model based on the rapid distortion theory (RDT) [15,16] is applied to account for the airfoil mean flow turbulence distortion present in the vicinity of the airfoil leading edge.…”

Section: Introductionmentioning

confidence: 99%

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Leading-Edge Noise Prediction of General Airfoil Profiles with Spanwise-Varying Inflow Conditions

2018

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This paper presents a study of the leading-edge noise radiated by an airfoil undergoing a turbulent inflow. The noise prediction of generic airfoil profiles subjected to spanwise-varying inflow conditions is performed with the support of Amiet's theory and the inverse strip technique. In the proposed methodology, the aeroacoustic transfer function of a generic airfoil profile is computed by the boundary element method. The effects of the airfoil leading-edge thickness on the inflow turbulence are accounted for by a turbulence spectrum based on the rapid distortion theory. This research shows that the turbulence distortion plays a significant role on the predicted noise levels. Compared with the von Kármán model for isotropic turbulence, the rapid distortion theory predicts reduced noise levels at high frequencies and increased noise levels at low frequencies. This paper also shows that the spanwise-varying inflow, here represented by a linearly changing condition, contributes to raising the noise levels when compared to the similar uniform inflow case. This research confirms that the finite airfoil thickness decreases the airfoil-gust lift response, consequently reducing the noise levels. This observation is more pronounced for microphones positioned downstream of the airfoil and for high frequencies.

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Section: Rapid Distortion Theorysupporting

confidence: 69%

Section: A Acoustic Radiation: Amiet's Theorymentioning

confidence: 99%

Section: B Aeroacoustic Transfer Function For General Airfoil Profilesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%