Vortex-Shedding Noise and Potential-Interaction Noise Modeling by a Reversed Sears' Problem

Roger, Michel; Moreau, Stéphane; Guedel, A.

doi:10.2514/6.2006-2607

Cited by 31 publications

(23 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As the angle-of-attack grows the main peak also shifts to slightly lower frequencies as vortex shedding begins to occur . Experiments on flat-plates and axial fans have shown similar spectral peaks at the during vortex shedding (Longhouse 1977, Roger et 2006. Noise is also produced when counter-rotating vortices interact.…”

Section: Dynamic Stall Noisementioning

confidence: 69%

A discussion of wind turbine interaction and stall contributions to wind farm noise

Laratro

Arjomandi

Kelso

et al. 2014

Journal of Wind Engineering and Industrial Aerodynamics

View full text Add to dashboard Cite

Elsevier's Policy: An author may use the preprint for personal use, internal institutional use and for permitted scholarly posting. ... Elsevier's AAM Policy: Authors retain the right to use the accepted author manuscript for personal use, internal institutional use and for permitted scholarly posting provided that these are not for purposes of commercial use or systematic distribution. Elsevier believes that individual authors should be able to distribute their AAMs for their personal voluntary needs and interests, e.g. posting to their websites or their institution's repository, e-mailing to colleagues. However, our policies differ regarding the systematic aggregation or distribution of AAMs to ensure the sustainability of the journals to which AAMs are submitted. Therefore, deposit in, or posting to, subject-oriented or centralized repositories (such as PubMed Central), or institutional repositories with systematic posting mandates is permitted only under specific agreements between Elsevier and the repository, agency or institution, and only consistent with the publisher's policies concerning such repositories. Voluntary posting of AAMs in the arXiv subject repository is permitted. ... Highlights-Rotor-wake interaction plays a role in wind farm noise -More wake data needs to be collected -Dynamic stall noise needs to be characterised AbstractWind farms have recently been reported to produce a noise signature that is described as possessing a "thumping" quality. Measurements of these signatures are limited and their effects are debated but their effect on public opinion and complaints make them a concern for researchers in this field. Proposed reasons for these noise signatures include amplitude modulation, interference patterns and wake-rotor interaction. This paper discusses these effects and concludes that wake-rotor interaction plays a role by causing variations in turbulent-inflow noise and dynamic stall. The current state of research into stall noise and wind turbine wake structure is also reviewed and it is concluded that the available information and collected data on wind turbine wake are insufficient to determine how strong this role is. More information on the velocity and turbulence fields in the wake of horizontal-axis wind turbines as well as a characterisation of the noise produced by an airfoil experiencing dynamic stall is required in order to make a full assessment of rotor-wake contributions to wind farm noise.2

show abstract

Section: Dynamic Stall Noisementioning

confidence: 69%

A discussion of wind turbine interaction and stall contributions to wind farm noise

Laratro

Arjomandi

Kelso

et al. 2014

Journal of Wind Engineering and Industrial Aerodynamics

View full text Add to dashboard Cite

show abstract

“…A Gaussian correlation coefficient with a spanwise length scale ℓ 0 is assumed. Other available investigations on flat plates of large chord-to-thickness ratio suggest that ℓ 0 ≃ 7 h [2], so this value is taken for granted in the present case, even though it is somewhat larger than the value for a cylinder. At the very low Mach number of interest for which M 0 ≪ 1, the peak intensity of vortex-shedding sound is expressed as…”

Section: Simplified Modelmentioning

confidence: 71%

“…Even though simple by virtue of its compactness, the presently investigated Katana blade can be treated by more general formulations as a special test case. The predictions made in this section are based on the analytical model of the vortex-shedding noise from a thin rigid flat-plate body with a blunted trailing edge proposed by Roger et al [2]. Since this less restrictive model deals with an arbitrary chord length, the corresponding calculations will be said non-compact here for convenience.…”

Section: Spectral Modelmentioning

confidence: 99%

Coupled oscillations in the aeroacoustics of a Katana blade

Roger

2008

The Journal of the Acoustical Society of America

Self Cite

View full text Add to dashboard Cite

The paper investigates experimentally the tonal characteristics of the aerodynamic sound of a Katana blade handled at high speed. Katana is the name of the Japanese sword used in martial arts. It is designed with a sharp cutting edge, a thick black-edge, and sometimes so-called blood-grooves. When handled through the air, the blade radiates sound at different frequencies. First a low-frequency, dominant sound is heard due to the von Karman vortex shedding in the wake of the blade. Second high-frequency tones are produced in the case of a Katana with grooves. The tones result from the self-sustained oscillations of the detached shear layers over the grooves which behave like cavities under a grazing flow. In the case of a Katana with no groove, other high-frequency tones are heard due to acoustic back-reaction on the Tollmien-Schlichting waves growing in the boundary layers. The variations of the acoustic signature with varying angle of attack and relative flow speed are analyzed in the paper, with emphasis on the coupling between the different mechanisms. The main trends are compared to simple self-sustained oscillation formulae. Finally the possible use of the sound as a criterion of inaccuracies in the handling of the Katana is discussed.

show abstract

“…Indeed, the transmission shaft radially positionned just downstream of the rotor for the latter plays the same obstruction role as the strut for the former. A strong tonal noise is generated in this case, for which an analytical model has been proposed by Roger et al [23,25], as follows. The distorted flow around any shaft cross-section is assimilated to the two-dimensional potential flow around a circle [26].…”

Section: Generic Potential-interaction Noise Modelmentioning

confidence: 99%

“…Azimuthal profiles of the upwash on the blades (normal to the chord) according to the potential-interaction model[25]. Configurations D1 (a) and D2 (b).…”

mentioning

confidence: 99%

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

Roger

Moreau

2020

Acoustics

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Vortex-Shedding Noise and Potential-Interaction Noise Modeling by a Reversed Sears' Problem

Cited by 31 publications

References 3 publications

A discussion of wind turbine interaction and stall contributions to wind farm noise

A discussion of wind turbine interaction and stall contributions to wind farm noise

Coupled oscillations in the aeroacoustics of a Katana blade

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

Contact Info

Product

Resources

About