Control of rotor trailing edge noise using porous additively manufactured blades

Jiang, Chaoyang; Moreau, Danielle; Yauwenas, Yendrew; Fischer, Jeoffrey; Doolan, Con J.; Gao, Jianzheng; Jiang, Weikang; McKay, Ryan S.; Kingan, Michael J.

doi:10.2514/6.2018-3792

Cited by 16 publications

(11 citation statements)

References 20 publications

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“…Several studies on this passive modification exist, including experimental studies on brush-like or slitted trailing edge extensions [1][2][3], on fully porous airfoils [4,5] and on airfoils with trailing edges modified by metal mesh sheets [6] or porous foams [7][8][9]. In addition, the availability of 3D printing technologies enables the use of porous trailing edges manufactured via rapid prototyping [10]. There are also approaches to combine the successful concept of serrated trailing edges with a porous modification [11].…”

Section: Introductionmentioning

confidence: 99%

Self Noise Reduction and Aerodynamics of Airfoils with Porous Trailing Edges

Geyer

Sarradj

2019

Acoustics

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The application of open-porous materials is a possible method to effectively reduce the aerodynamic noise of an airfoil. However, the porous consistency may have a negative effect on the aerodynamic performance of the airfoil, since very often the lift is decreased while the drag increases. In a recent investigation, the generation of trailing edge noise of a set of airfoil models made from different porous materials was examined experimentally. The materials were characterized mainly by their airflow resistivity. Besides the material, the chordwise extent of the porous material was varied, which was done by covering the front part of the porous airfoil with a thin, impermeable adhesive foil. Acoustic measurements were performed in an open jet wind tunnel using microphone array technology, while the aerodynamic performance was measured simultaneously using a six-component balance. In general, both the airflow resistivity and the extent of the porous material have an influence on the trailing edge noise. However, if a suitable material is chosen, the results show that a noticeable reduction of trailing edge noise is possible even with only a small chordwise extent of the porous material.

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Section: Introductionmentioning

confidence: 99%

Self Noise Reduction and Aerodynamics of Airfoils with Porous Trailing Edges

Geyer

Sarradj

2019

Acoustics

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“…Recently developed manufacturing techniques such as 3D-printing [21] allow constructing permeable trailing edge inserts simply connecting suction and pressure sides of the airfoil with straight channels [22]. This possibility is specially interesting since it would allow to manufacture trailing edges with tailored permeability.…”

Section: Introductionmentioning

confidence: 99%

3D-printed Perforated Trailing Edges for Broadband Noise Abatement

Carpio

Avallone

Ragni

et al. 2019

25th AIAA/CEAS Aeroacoustics Conference

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Turbulent boundary layer trailing-edge noise scattered by a NACA0018 airfoil equipped with 3D printed perforated trailing-edge inserts, i.e. with straight cylindrical channels connecting the two sides of the airfoil, is investigated. The inserts have different permeability in order to assess the effect of this property on broadband noise generation. Far-field noise is measured with a phased microphone array. The experiments are performed at free-stream velocities of 26 and 41 m/s, corresponding to chord-based Reynolds numbers of 3.4×10 5 and 5.4×10 5 , and at angles of attack of 0 and 4.8 •. The inserts, with permeability values of 1.5×10 −9 and 5.4×10 −9 m 2 , attenuate respectively up to 5 and 9.5 dB at 0 • and up to 4 and 7.5 dB at 4.8 • incidence. The noise abatement of inserts with straight passages is compared with that of inserts manufactured using metallic foams with a random pore distribution but similar permeability. It is found that to achieve similar overall noise attenuation levels, the perforated inserts require at least 3 times higher permeability than the metal foam inserts. From this we conclude that in order to maximize the noise attenuation potential of permeable inserts, the inner structure of the permeable trailing-edge insert must be considered.

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“…3D printing) has grown very fast and has now made possible to directly integrate porous material structures into airfoil and rotor blade. Jiang et al [62] carried out an experimental analysis on the effect on the TE noise of porosity employed on a rotor rig. Porous materials have already been used to control flat plate noise generation [46,47,63].…”

Section: Porous Materials Insertsmentioning

confidence: 99%

Small-Scale Rotor Aeroacoustics for Drone Propulsion: A Review of Noise Sources and Control Strategies

Candeloro¹,

Pagliaroli²,

Ragni³

et al. 2019

Preprint

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In the last decade, the drone market has grown rapidly for both civil and military purposes. Due to their versatility, drones demand is constantly increasing, with several industrial players joining the venture to transfer urban mobility to the air. This has exacerbated the problem of noise pollution, mainly due to the relatively lower altitude of these vehicles and to the proximity of their routes to extremely densely populated areas. In particular, both the aerodynamic and aeroacoustic optimization of the propulsive system and of its interaction with the airframe are key aspects of the design of aerial vehicles for the success or the failure of their mission. The industrial challenge involves finding the best performance in terms of loading, efficiency and weight, and, at the same time, the most silent configuration. For this reason, research has focused on an initial localization of the noise sources and, on further analysis, of the noise generation mechanism, focusing particularly on directivity and scattering. The aim of the present study is to review the noise source mechanisms and the state-of-the-art technologies available in literature for its suppression, focusing especially on the fluid-dynamic aspects of low Reynolds numbers of the propulsive system and on the interaction of the propulsive-system flow with the airframe.

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Control of rotor trailing edge noise using porous additively manufactured blades

Cited by 16 publications

References 20 publications

Self Noise Reduction and Aerodynamics of Airfoils with Porous Trailing Edges

Self Noise Reduction and Aerodynamics of Airfoils with Porous Trailing Edges

3D-printed Perforated Trailing Edges for Broadband Noise Abatement

Small-Scale Rotor Aeroacoustics for Drone Propulsion: A Review of Noise Sources and Control Strategies

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