scholarly journals Noise reduction mechanisms of an open-cell metal-foam trailing edge

2020 ◽  
Vol 898 ◽  
Author(s):  
C. Teruna ◽  
F. Manegar ◽  
F. Avallone ◽  
D. Ragni ◽  
D. Casalino ◽  
...  
Keyword(s):  
Noise Reduction ◽  
Metal Foam ◽  
Trailing Edge ◽  
Open Cell ◽  
Reduction Mechanisms ◽  
Image Position

Numerical study on the airfoil self-noise of three owl-based wings with the trailing-edge serrations

2021 ◽  
pp. 095441002098822
Author(s):  
Dian Li ◽  
Xiaomin Liu ◽  
Lei Wang ◽  
Fujia Hu ◽  
Guang Xi
Keyword(s):  
Flow Field ◽  
Noise Reduction ◽  
Numerical Study ◽  
Barn Owl ◽  
Aerodynamic Noise ◽  
Frequency Noise ◽  
Trailing Edge ◽  
Reduction Mechanisms ◽  
Trailing Edge Serrations ◽  
Bionic Airfoil

Previous publications have summarized that three special morphological structures of owl wing could reduce aerodynamic noise under low Reynolds number flows effectively. However, the coupling noise-reduction mechanism of bionic airfoil with trailing-edge serrations is poorly understood. Furthermore, while the bionic airfoil extracted from natural owl wing shows remarkable noise-reduction characteristics, the shape of the owl-based airfoils reconstructed by different researchers has some differences, which leads to diversity in the potential noise-reduction mechanisms. In this article, three kinds of owl-based airfoils with trailing-edge serrations are investigated to reveal the potential noise-reduction mechanisms, and a clean airfoil based on barn owl is utilized as a reference to make a comparison. The instantaneous flow field and sound field around the three-dimensional serrated airfoils are simulated by using incompressible large eddy simulation coupled with the FW-H equation. The results of unsteady flow field show that the flow field of Owl B exhibits stronger and wider-scale turbulent velocity fluctuation than that of other airfoils, which may be the potential reason for the greater noise generation of Owl B. The scale and magnitude of alternating mean convective velocity distribution dominates the noise-reduction effect of trailing-edge serrations. The noise-reduction characteristic of Owl C outperforms that of Barn owl, which suggests that the trailing-edge serrations can suppress vortex shedding noise of flow field effectively. The trailing-edge serrations mainly suppress the low-frequency noise of the airfoil. The trailing-edge serration can suppress turbulent noise by weakening pressure fluctuation.

scholarly journals Numerical Analysis of Metal-Foam Application for Trailing Edge Noise Reduction

2019 ◽  
Author(s):  
Christopher Teruna ◽  
Farhan A. Manegar ◽  
Francesco Avallone ◽  
Damiano Casalino ◽  
Daniele Ragni ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Noise Reduction ◽  
Metal Foam ◽  
Trailing Edge ◽  
Trailing Edge Noise

Prediction of aerodynamic noise reduction by using open-cell metal foam

2012 ◽  
Vol 331 (7) ◽  
pp. 1483-1497 ◽  
Author(s):  
Hanru Liu ◽  
Jinjia Wei ◽  
Zhiguo Qu
Keyword(s):  
Noise Reduction ◽  
Metal Foam ◽  
Aerodynamic Noise ◽  
Open Cell

Trailing-edge noise reduction of a wing by a surface modification

2021 ◽  
Vol 263 (3) ◽  
pp. 3194-3201
Author(s):  
Varun Bharadwaj Ananthan ◽  
R.A.D. Akkermans ◽  
Dragan Kozulovic
Keyword(s):  
Noise Reduction ◽  
Stochastic Approach ◽  
Slight Reduction ◽  
Noise Sources ◽  
Trailing Edge ◽  
Sound Sources ◽  
Airframe Noise ◽  
Trailing Edge Noise ◽  
Random Particle ◽  
Noise Production

There is an increased emphasis on reducing airframe noise in the last decades. Airframe noise is sound generated by the interaction of a turbulent flow with the aircraft geometry, and significantly contributes to the overall noise production during the landing phase. One examples of airframe noise is the noise generated at a wing's trailing edge, i.e., trailing-edge noise. In this contribution, we numerically explore the local application of riblets for the purpose of trailing-edge noise reduction. Two configurations are studied: i) a clean NACA0012 wing section as a reference, and ii) the same configuration with riblets installed at the wing's aft part. The numerical investigation follows a hybrid computational aeroacoustics approach, where the time-average flow is studied by means of RANS. Noise sources are generated by means of a stochastic approach called Fast Random Particle Mesh method. The results show a deceleration of the flow behind the riblets. Furthermore, the turbulent kinetic energy indicates increased unsteadiness behind the riblets which is shifted away from the wall due to the presence of the riblets. Lastly, the sound sources are investigated by means of the 3D Lamb-vector, which indicates a slight reduction in magnitude near the trailing edge.

Experimental study of particulate fouling in partially filled channel with open-cell metal foam

2020 ◽  
Vol 110 ◽  
pp. 109941 ◽  
Author(s):  
F. Shikh Anuar ◽  
Kamel Hooman ◽  
M.R. Malayeri ◽  
Iman Ashtiani Abdi
Keyword(s):  
Experimental Study ◽  
Metal Foam ◽  
Open Cell ◽  
Particulate Fouling
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