Noise Reduction of UAV Using Biomimetic Propellers with Varied Morphologies Leading-edge Serration

Wei, Yunjie; Xu, Feng; Bian, Shiyuan; Kong, Deyi

doi:10.1007/s42235-020-0054-z

Cited by 28 publications

(18 citation statements)

References 34 publications

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“…It seems from their Fig. 10b in Wei et al [13]) that the hook-like serrations changed the direction of flow. However, since the graph is cut downstream at about 0.5 of serration length, it is difficult to infer a concluding answer on any flow turning.…”

Section: Comparison With Other Workmentioning

confidence: 90%

“…A vague indication of flow turning may be found in the results from Wei et al [13], although not mentioned therein. It seems from their Fig.…”

Section: Comparison With Other Workmentioning

confidence: 93%

“…Each of the serrations generates a vortex pair, which stabilizes the flow similar as vortex generators do. Wei et al [13] applied such serrations on the wing of a propeller to shift the location of laminar-to-turbulent transition on the suction side. Ikeda et al [12] investigated different length of the serrations to find the optimum of lift-to-drag ratio at angles of attack < 15 • .…”

Section: Introductionmentioning

confidence: 99%

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Flow turning effect and laminar control by the 3D curvature of leading edge serrations from owl wing

Muthuramalingam¹,

Talboys²,

Wagner³

et al. 2020

Bioinspir. Biomim.

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This work describes a novel mechanism of laminar flow control of straight and backward swept wings with a comb-like leading edge device. It is inspired by the leading-edge comb on owl feathers and the special design of its barbs, resembling a cascade of complex 3D-curved thin finlets. The details of the geometry of the barbs from an owl feather were used to design a generic model of the comb for experimental and numerical flow studies with the comb attached to the leading edge of a flat plate. Due to the owls demonstrating a backward sweep of the wing during gliding and flapping from live recordings, our examinations have also been carried out at differing sweep angles. The results demonstrate a flow turning effect in the boundary layer inboards, which extends downstream in the chordwise direction over distances of multiples of the barb lengths. The inboard flow-turning effect described here, counteracts the outboard directed cross-span flow typically appearing for backward swept wings. This flow turning behavior is also shown on SD7003 airfoil using precursory LES investigations. From recent theoretical studies on a swept wing, such a way of turning the flow in the boundary layer is known to attenuate crossflow instabilities and delay transition. A comparison of the comb-induced cross-span velocity profiles with those proven to delay laminar to turbulent transition in theory shows excellent agreement, which supports the laminar flow control hypothesis. Thus, the observed effect is expected to delay transition in owl flight, contributing to a more silent flight.

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Section: Comparison With Other Workmentioning

confidence: 90%

“…A vague indication of flow turning may be found in the results from Wei et al [13], although not mentioned therein. It seems from their Fig.…”

Section: Comparison With Other Workmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

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Flow turning effect and laminar control by the 3D curvature of leading edge serrations from owl wing

Muthuramalingam¹,

Talboys²,

Wagner³

et al. 2020

Bioinspir. Biomim.

View full text Add to dashboard Cite

show abstract

“…Multi-rotor drones employ a wide range of propellers. Serrated features in the leading edge of some propellers have been demonstrated to be effective at reducing noise levels (Wei et al, 2020). However, many propellers are intended to keep the flow on the wing surface smooth and to prevent flow separation, so the importance of the leading-edge serration in controlling the boundary layer (Ikeda et al, 2018) may be restricted.…”

Section: Aerodynamic Performance and Noise Level Of Normal Propellermentioning

confidence: 99%

Characterization of the low-noise drone propeller with serrated Gurney flap

Noda¹,

Ikeda²,

Nakata³

et al. 2022

Front. Aerosp. Eng.

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Drones, which have become increasingly popular in recent years, produce a lot of noise due to the movement of their propellers. When flying near humans, especially as in urban situations, noise suppression is critical. It has been demonstrated that noise can be minimized by increasing propeller lift per unit rotation speed and decreasing propeller rotation speed by expanding propeller area or designing the airfoil shape. This study developed a new structure, serrated Gurney flap, by merging the Gurney flap, which is the trailing-edge structure of an airfoil, and the serration, which is the low-noise structure found in an owl feather, and studied its performance through experiments and numerical simulations. The results indicated that the structure can boost the propeller’s lift coefficient while reducing the vortex separation induced by the Gurney flap and suppress propeller noise by slowing the propeller. Further modification of its structure may result in improved efficiency as well as decreased noise level.

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“…Over millions of years of evolution, the biological structures have developed excellent properties and ingenious frames, which provide a large number of innovative models for solving engineering problems and improving design methods. [24][25][26] After analyzing the body configuration and skeleton structure of a manta ray in swimming, a bionic mold with deflectors is developed in this paper, which can improve the thermal performance of the mold plate during the autoclave curing process as well as reducing the structure weight. The remainder of this paper is organized as follows: Firstly, the structure of the bionic mold is introduced in detail and the stiffness of the bionic mold is analyzed.…”

Section: Introductionmentioning

confidence: 99%

A manta-ray-inspired bionic curing mold for autoclave process of composite manufacturing

Lin

Wang

et al. 2022

Journal of Reinforced Plastics and Composites

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The temperature distribution of the mold is directly linked to the manufacturing quality of the composite component. In this paper, a bionic mold based on the analysis of a manta ray in swimming is developed to improve the thermal performance of the mold during the autoclave curing process. The bionic mold has fewer frames and better air permeability, and the mold weight is decreased by 42.95% while the stiffness is proved to satisfy the requirement. The model of the autoclave curing process which is verified by experiments is established to carry out the thermal analysis of the mold. Results show that the air velocity in the mold is increased with the bionic design, which can reduce not only the maximum temperature difference of the mold plate (−30.35%) but also the percentage of low-temperature areas. Besides, the heating rate and the heat preservation time of the mold are also improved.

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Noise Reduction of UAV Using Biomimetic Propellers with Varied Morphologies Leading-edge Serration

Cited by 28 publications

References 34 publications

Flow turning effect and laminar control by the 3D curvature of leading edge serrations from owl wing

Flow turning effect and laminar control by the 3D curvature of leading edge serrations from owl wing

Characterization of the low-noise drone propeller with serrated Gurney flap

A manta-ray-inspired bionic curing mold for autoclave process of composite manufacturing

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