Reducing Aerodynamic Noise in a Rod-Airfoil Using Suction and Blowing Control Method

Abbasi, Sarallah; Souri, Maryam

doi:10.1142/s1758825120500362

Cited by 23 publications

(5 citation statements)

References 37 publications

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“…Szőke [7] found that suction could reduce the trailing edge noise of a flat airfoil. Abbasi et al [8] proved that suction control was also applicable to the flow around the airfoil with the addition of rod interference.…”

Section: Introductionmentioning

confidence: 99%

Control of separated flow at low Reynolds number around NACA0012 airfoil by boundary layer suction

Wang,

Lai

2024

J. Phys.: Conf. Ser.

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The separated flow at low Reynolds number around the NACA0012 airfoil is numerically studied by large-eddy simulation. Strategies of boundary layer suction to control flow separation are investigated. A method of using two-zone suctions, near the leading edge and near the trailing edge, are calculated. Based on verification with direct numerical simulation (DNS) and experimental data, the results of the lift and the drag, the vortices, and the strength of near-field pressure fluctuations, are checked. The results show that the two-zone suctions can supress flow transition and separation, thereby increase the lift and reduce the drag. The shedding of vortices is weakened, and the near-field pressure fluctuations are attenuated. For comparison with the two-zone suctions, the strategies of suction near the leading edge only and suction near the trailing edge only are also studied. It is found that suction near the leading edge only may suppress transition and delay separation when the suction zone is large enough, but the flow property deteriorates due to shedding vortices in the wake. The suction near the trailing edge only may improve the flow performance by reducing the size of the vortices in the rear section of the airfoil and in the wake region, but it has little effect on the separation bubble and transition.

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Section: Introductionmentioning

confidence: 99%

Control of separated flow at low Reynolds number around NACA0012 airfoil by boundary layer suction

Wang,

Lai

2024

J. Phys.: Conf. Ser.

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“…Studies on airfoil design and optimization have been conducted to directly decrease the noise emissions by adjusting the aerodynamic shape [1][2][3], such that the suction side of the boundary layer flow perturbation near the trailing edge is suppressed. The boundary layer flow injection/suction treatments at the airfoil trailing edge [4,5] have been investigated, which, combined with a control strategy, showed that a considerate decrease in noise was achieved due to the suppression and alleviation of vortices. Several methods inspired by bionics have been developed, such as serrations applied at the airfoil leading edge and trailing edge [6][7][8] and finlets for rotor noise reduction [9,10], and both add-ons showed good performance in noise reduction by either limiting the magnitude or spanwise correlation length-scale of the turbulence.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on Flow and Noise Characteristics of an NACA0018 Airfoil with a Porous Trailing Edge

et al. 2022

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An airfoil with a porous trailing edge has a low noise emission; thus, using a porous medium is a good technique for further reduction of wind turbine noise. In this paper, to reduce airfoil trailing edge noise while minimizing the negative influence of a porous medium on aerodynamic performance, a new filling method is proposed such that a porous medium is only used in the suction side half of the trailing edge, which is more sensitive to the noise generation. The large eddy simulation (LES) technique for flow and the Ffowcs Williams and Hawkings (FW-H) method for acoustics are used. At a Reynolds number of 2.63 × 105 and various angles of attack, an NACA0018 airfoil profile with a porous trailing edge covering 20% of the chord is studied under two porous configurations, namely a fully porous and a suction-side porous trailing edge type. The results show that the flow direction, velocity magnitude, and their distributions along the boundary layer of the two porous airfoils are significantly modified due to the presence of the porous medium. The fluctuation of the pressure coefficient and the increase in the boundary layer thickness are significant at low angles of attack. As compared to the solid airfoil counterpart, the noise radiation from the newly proposed suction-side porous airfoil achieves a noise reduction of 4.3 dB at an angle of attack α = 0°, and a noise reduction of 4.07 dB at an angle of attack α = 2°.

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“…Various studies have been conducted in this field, but little research has been done on the effects of using this method on the aerodynamic noise properties. For example, Abbasi and Souri used simultaneous suction and blowing to reduce aerodynamic noise in a rod -airfoil configuration Souri 2020, Abbasi andSouri 2021a). Mathelin et al (2002) experimentally examined the heat transfer around a cylinder containing blowing slot windows.…”

Section: Introductionmentioning

confidence: 99%

Effects of Blowing Location on Aeroacoustics of the Flow over a Circular Cylinder

2022

JAFM

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This study investigated the effect of blowing on vortex shedding and aerodynamic noise due to flow over a circular cylinder. The flow simulation is performed by the URANS equations using k-ω-SST turbulence model. Calculations of the aerodynamic noise are performed through F-fowcs Williams-Hawkins analogy. The cylinder's cross-section with a diameter of D=16mm, and the blowing jet is applied through slot windows that are located on the cylinder back surface. In this study, three positions for slot windows are considered. Verification of the numerical results is confirmed by comparing numerical results with the reported experimental ones (Uncontrolled case). The results showed that the optimal blowing position could reduce noise, lift coefficient, and drag coefficient; this result occurs for a slot window located near the cylinder horizontal axis of symmetry. On the other hand, if the blowing slot is located at the cylinder symmetric vertical axis, the aerodynamic noise increases by approximately 4 dB. In this case, the average lift and drag fluctuations are increased by more than 200%. The present study gives a new idea to the reduction of noise of the single body systems.

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Reducing Aerodynamic Noise in a Rod-Airfoil Using Suction and Blowing Control Method

Cited by 23 publications

References 37 publications

Control of separated flow at low Reynolds number around NACA0012 airfoil by boundary layer suction

Control of separated flow at low Reynolds number around NACA0012 airfoil by boundary layer suction

Numerical Study on Flow and Noise Characteristics of an NACA0018 Airfoil with a Porous Trailing Edge

Effects of Blowing Location on Aeroacoustics of the Flow over a Circular Cylinder

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