Tandem cylinder aerodynamic sound control using porous coating

Liu, Hanru; Azarpeyvand, Mahdi; Wei, Jinjia; Qu, Zhiguo

doi:10.1016/j.jsv.2014.09.013

Cited by 87 publications

(54 citation statements)

References 46 publications

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“…The currently available approaches can be categorized as passive methods and active methods. The examples of the former one include the application of TE serrations, [10][11][12][13][14][15][16][17] TE brushes, 18,19 porous material, [20][21][22][23][24][25] surface treatments, [26][27][28][29] shape optimization and morphing, 30 etc. The efficiency of the passive methods is limited to a given range of conditions and out of this range they might introduce undesired losses.…”

Section: Nomenclaturementioning

confidence: 99%

Active Flow Control Methods for the Reduction of Trailing Edge Noise

Szoke

Azarpeyvand

2017

23rd AIAA/CEAS Aeroacoustics Conference

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General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. The possibility of trailing edge noise reduction using active flow control is addressed in this paper. The boundary layer is altered with the help of uniform perpendicular and inclined flow injection and suction on a long flat plate upstream of a sharp trailing edge. The flow quantities have been measured using particle image velocimetry, hot-wire anemometry, and the surface pressure fluctuations using flush mounted miniature pressure transducers. It was shown that the proposed flow control methods are capable of reducing the noise over a wide range of frequencies. It was also revealed that the perpendicular blowing is effective in shifting the energy containing turbulent structures away from the wall, resulting in a significant reduction in the surface pressure spectra. The inclined blowing control method was capable of further reducing the surface pressure spectra, while maintaining low input power requirement. The perpendicular suction control was shown to be effective in the reduction of pressure fluctuations in the mid frequency regions, which quickly penetrates to the lower frequency downstream. The inclined suction control has also lead to significant reductions in the surface pressure fluctuations over a wide range of frequencies, while the required suction rate was kept considerably low. It has also been shown that the proposed active flow control methods can reduce the spanwise correlation length of the turbulent structures near the trailing edge. In general, results have shown that all proposed active flow control techniques can effectively alter the boundary layer structure and reduce trailing edge noise. Nomenclature

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Section: Nomenclaturementioning

confidence: 99%

Active Flow Control Methods for the Reduction of Trailing Edge Noise

Szoke

Azarpeyvand

2017

23rd AIAA/CEAS Aeroacoustics Conference

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“…One possible method for the reduction of aeroacoustic noise from cylinders is the use of flow permeable materials, which has been the subject of various studies in the past. This includes both experimental investigations [1][2][3][4][5][6][7] and numerical work [8][9][10][11]. In addition to a reduction of noise, such materials also affect the flow around the cylinder and, subsequently, the aerodynamic drag [12][13][14][15][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Detached Eddy Simulation of the Flow Noise Generation of Cylinders with Porous Cover

Geyer

Sharma

Sarradj

2018

2018 AIAA/CEAS Aeroacoustics Conference

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The use of porous materials is a known method for the reduction of cylinder vortex shedding noise. In a previous experimental wind tunnel study, the noise reducing effect of a modification of circular cylinders with open-porous materials was shown. The cylinder models consisted of a solid core cylinder with porous covers with different material parameters. In order to obtain insight into the flow through the porous materials, the noise generation by such porous-covered cylinders is investigated numerically using Detached-Eddy Simulations. This was done for three different porous material covers as well as for a non-porous reference cylinder at three Reynolds numbers in the critical flow regime. Unlike the observations from the experiments, the numerical results show that fluid enters the porous materials and vortex shedding also takes place at the inner core cylinder, leading to an additional tone in the acoustic far field spectrum. In addition, the porous covers were found to have no effect on the directivity of the aeolian tone and to lead to a notable reduction of the aerodynamic drag.

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“…As such, airfoil self-noise has been considered as an important component of airframe noise during take-off and landing. Some of the currently employed passive methods for airfoil trailing edge noise reduction includes serrated trailing edges [3,4], porous surface treatments [5][6][7][8] and morphing trailing edges [9][10][11][12]. With the use of morphing surfaces our aim is to address transition delay, separation postponement, lift enhancement, drag reduction, turbulence augmentation and noise suppression [13].…”

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confidence: 99%

Aerodynamic and Aeroacoustic Performance of Airfoils Fitted with Morphing Trailing-edges

Jawahar

Azarpeyvand

Silva

2018

2018 AIAA/CEAS Aeroacoustics Conference

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Experimental and numerical studies of a simple NACA 0012 airfoil fitted with two different flap profiles were successfully carried out to characterize their aerodynamic and aeroacoustic performance. The airfoil was tested with two flap configurations with different flap camber and a flap deflection angle of β = 10 • . The aerodynamic lift and drag measurements show improved lift-to-drag performance for the morphed flap airfoil. Surface flow visualization has shown delayed separation for the morphed flap airfoil. Flow measurements showed that the downstream wake development can be significantly influenced by the flap profile. Particle Image Velocimetry was used to study the flow over the flap and airfoil wake. The tests were carried out for a flow velocity of U ∞ = 20 m/s, corresponding to a chord-based Re c = 2.6 × 10 5 . The mean velocity contours at the wake showed increased wake deficit and turbulent kinetic energy for the morphed flap airfoil compared to the hinged flap airfoil. The turbulent kinetic energy results displayed a characteristic double peak behavior which was also the dominant content of the streamwise normal Reynolds shear stress component. Large eddy simulations were carried out for the two airfoils and the results were validated with the experimental measurements. The boundary layer profile from the computations showed delayed separation. The wall pressure spectra close to the trailing edge showed increased energy for the morphed flap airfoil relative to the hinged flap airfoil. The Curle's acoustic analogy was used to calculate the far-field noise measurements and morphed flap airfoil showed increased noised compared to the hinged flap airfoil.

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Tandem cylinder aerodynamic sound control using porous coating

Cited by 87 publications

References 46 publications

Active Flow Control Methods for the Reduction of Trailing Edge Noise

Active Flow Control Methods for the Reduction of Trailing Edge Noise

Detached Eddy Simulation of the Flow Noise Generation of Cylinders with Porous Cover

Aerodynamic and Aeroacoustic Performance of Airfoils Fitted with Morphing Trailing-edges

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