Multirotor Drone Noise at Static Thrust

Tinney, Charles E.; Sirohi, Jayant

doi:10.2514/1.j056827

Cited by 135 publications

(45 citation statements)

References 15 publications

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“…Two configurations are considered for the study. The configuration D1 is close to the well-documented drone Cyclone investigated by Misiorowski et al [18] and to the one reported by Tinney and Sirohi [17]. The configuration D2 is more representative of the DJI Phantom II studied by Intaratep et al [6], or of the Hubsan X4-Pro.…”

Section: Basic Aerodynamic Features Of Quadrotorssupporting

confidence: 82%

“…If noise enters the optimisation strategy as a criterion, unsteady loads must be considered as well. Consequently, the present work addresses realistic model distortions encountered in typical drone architectures, such as described in [6,17]. Two distortions are retained, namely the side-flow induced by advancing flight and the potential distortion around the supporting struts of a rotor.…”

Section: Introductionmentioning

confidence: 99%

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Tonal-Noise Assessment of Quadrotor-Type UAV Using Source-Mode Expansions

Roger

Moreau

2020

Acoustics

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The present work deals with the modeling of the aerodynamic sound generated by the propellers of small-size drones, taking into account the effects of horizontal forward flight with negative pitch and of installation on supporting struts. Analytical aeroacoustic formulations are used, dedicated to the loading noise. The fluctuating lift forces on the blades are expanded as circular distributions of acoustic dipoles, the radiated field of which is calculated by using the free-space Green’s function. This provides descriptions of the sound field, valid in the entire space. The stationary mean-flow distortions responsible for the lift fluctuations and at the origin of the sound are estimated from existing numerical flow simulations and from ad hoc models. Installation and forward-flight effects are found to generate much more sound than the steady loading on the blades associated with thrust. Therefore, the models are believed reliable fast-running tools that could be used for preliminary low-noise design through repeated parametric calculations, or for noise-impact estimates corresponding to prescribed urban traffic.

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Section: Basic Aerodynamic Features Of Quadrotorssupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Tonal-Noise Assessment of Quadrotor-Type UAV Using Source-Mode Expansions

Roger

Moreau

2020

Acoustics

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“…Several concepts of DEP exist in the literature [11][12][13], but most of them are analysed for their applicability in designing BLI configurations [14,15]. Few studies have been conducted so far on the aeroacoustic properties of interacting propellers and are mainly related to counter-rotating propellers [16,17] and drones [18][19][20][21][22], where the distance between rotor hubs is a crucial aspect. In Reference [23], numerical aeroacoustic analyses of innovative propeller geometries have been carried out, accounting for a single propeller mounted on a wing.…”

Section: Introductionmentioning

confidence: 99%

Numerical Characterisation of the Aeroacoustic Signature of Propeller Arrays for Distributed Electric Propulsion

et al. 2020

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This paper presents an investigation of the aerodynamic and aeroacoustic interaction of propellers for distributed electric propulsion applications. The rationale underlying the research is related to the key role that aeroacoustics plays in the establishment of the future commercial aviation scenario. The sustainable development of airborne transportation system is currently constrained by community noise, which limits the operations of existing airports and prevents the building of new ones. In addition, the substantial saturation of the existing noise abatement technologies inhibits the further development of the existing fleet, and imposes the adoption of disruptive configurations in terms of airframe layout and propulsion technology. Simulation-based data may help in clarifying many aspects related to the acoustic impact of such innovative concepts. Blended-wing-body equipped with distributed electric propulsion is one of the most promising, due to the beneficial effect of the substantial shielding induced by its geometry. Nevertheless, the novelty of the layout requires a thorough investigation of specific aspect for which no previous experience is available. Herein, the interaction between propellers is analysed for a fixed propeller geometry, as a function of their mutual distance and compared to the acoustic pattern of the isolated one. The aerodynamic results have been obtained using a boundary integral formulation for unsteady, incompressible, potential flows which accounts for the interaction between free wakes and propellers. For the aeroacoustic analyses, the Farassat 1A boundary integral formulation for the solution of the Ffowcs Williams and Hawkings equation has been used. These results provide an insight into the minimum distance between propellers to avoid aerodynamic/aeroacoustic interaction effects, which is an important starting point for the development of distributed propulsion systems.

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“…The PSD estimate was also examined using premultiplied spectra [19], with the goal of filtering noise to clearly show contributions of the blade pass frequency (BPF) harmonics. The PSD for premultiplied spectra was calculated with segments of length = 2 /Ω where Ω is the rotational speed.…”

Section: Data Reductionmentioning

confidence: 99%

“…where ( ) is the Heaviside step function and: There are numerous other wavelets available for analysis, each with relative merits [19,20,22,24], but the Morse wavelet is well-supported by the cwt() function [25] and can be configured for different use cases. The generalized Morse wavelet is parameterized with the time-bandwidth product, 2 = :…”

Section: Data Reductionmentioning

confidence: 99%

Aerodynamic and Aeroacoustic Performance of Small UAV Propellers in Static Conditions

Jordan

Deters

Narsipur³

2020

Aiaa Aviation 2020 Forum

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The proliferation of small multi-rotor UAVs in commercial, recreational, and surveillance spheres has garnered significant interest in the noise produced by these vehicles. The current research aims to study the relationship between the aerodynamic performance and acoustic characteristics of small-scale UAV propellers. Three commercially available propellers for the DJI Phantom 2/3 UAV were selected for preliminary development and validation of an aeroacoustic experimental test setup and associated data reduction methods. Propeller thrust, torque, and power measurements were recorded at static conditions. Upon successful validation of the test bench, acoustic measurements were taken at the propeller disk's upstream and in-plane locations. The power spectral density of these acoustic signals was estimated using the modified periodogram (Welch's) method to identify frequency content and calculate sound pressure levels (SPLs) at each of the observation locations. Additionally, time-frequency analysis verified the periodogram results and identified possible sources of transient noise at static thrust. These methods found the nonrotor noise to be a major contributor to the SPL at higher frequencies and the propeller noise dominating the SPL spectra at the lower frequencies. Experimental thrust, torque, power, and sound pressure level (SPL) data were then compared for each propeller to identify relationships between aerodynamic performance and acoustic characteristics with variations in propeller geometry and blade loading.

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Multirotor Drone Noise at Static Thrust

Cited by 135 publications

References 15 publications

Tonal-Noise Assessment of Quadrotor-Type UAV Using Source-Mode Expansions

Tonal-Noise Assessment of Quadrotor-Type UAV Using Source-Mode Expansions

Numerical Characterisation of the Aeroacoustic Signature of Propeller Arrays for Distributed Electric Propulsion

Aerodynamic and Aeroacoustic Performance of Small UAV Propellers in Static Conditions

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