Vortex Model and Blade Span Influence on Orthogonal Blade-Vortex Interaction Noise

Zehner, Paul; Falissard, Fabrice; Gloerfelt, Xavier

doi:10.2514/1.j058878

Cited by 5 publications

(2 citation statements)

References 34 publications

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“…These outcomes suggest that the order of numerical scheme does not impact on the steady aerodynamic characteristics but on the wake flow unsteadiness, which may affect the acoustic performances. As mentioned in [20], the viscous wake or the tip vortex interaction [12,21,22] between the rotors plays a vital role for the tone noise and the broadband noise for the CROR configuration.…”

Section: Wake Analysismentioning

confidence: 99%

Noise Prediction of an Open Fan Using Acoustic Analogy Approaches

Sugiyama,

Falissard,

Reboul

et al. 2023

inter noise

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The purpose of this study is to evaluate numerical aero-acoustic methods for the noise prediction of an open fan, which is expected to reduce CO2 emissions for the next generation of aircraft engines. The far-field noise is computed using a CFD/CAA approach. The unsteady Reynolds Averaged Navier-Stokes (uRANS) and the Ffowcs Williams-Hawkings (FWH) analogy using solid and permeable surfaces are applied. The phase-lag method (single-blade passage) is used for the purpose of calculation for aerodynamic flow and noise sources with ONERA elsA finite volume solver. The sensitivities to the numerical CFD setup as well as the position and formulation of FWH permeable surface for noise computation are discussed in this paper. The present noise prediction strategy is evaluated for approach and take-off operating conditions. In particular, several spatial discretization schemes and FWH surface locations are tested and compared to evaluate their influence on the noise levels and directivity.

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Section: Wake Analysismentioning

confidence: 99%

Noise Prediction of an Open Fan Using Acoustic Analogy Approaches

Sugiyama,

Falissard,

Reboul

et al. 2023

inter noise

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“…BVI is the phenomenon in which the tip vortex trailing from the rotor tip directly strikes with the following blades during low-speed descending flight or maneuvers, resulting in strong fluctuations in the aerodynamic load on the blade surface. This process causes significant BVI noise, which is essentially a kind of vortex-induced aerodynamic noise [3,4]. The studies in tip vortex formation, evolution, and vortex dynamics have been an increasingly active research field [5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of an Unsteady Blade Surface Blowing Method to Reduce Rotor Blade-Vortex Interaction Noise

Sun

Shi

2022

International Journal of Aerospace Engineering

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This paper presents a numerical investigation of unsteady surface blowing using periodic variations of jet velocity with azimuthal angle to reduce helicopter rotor blade-vortex interaction (BVI) noise. The unsteady blowing is modeled as the mass flow outlet boundary condition of time-varying jet velocity on the blade surface grid using computational fluid dynamics. The same high-resolution overset grid system and flow/noise solver are used to perform a detailed flow field simulation and noise prediction for the nonblowing baseline case and the steady/unsteady blowing cases under the rotor BVI condition, and a grid convergence study for the steady and unsteady blowing cases is carried out. The BVI noise reduction and rotor thrust coefficient results of the unsteady blowing method and the previously published steady blowing with constant jet velocity are then compared. The noise reduction level of unsteady blowing is approximately equivalent to that of steady blowing (noise reduction is more than 3 dB). However, the loss in rotor thrust coefficient caused by unsteady blowing (3.3%) is only half of that by steady blowing (6.3%); the air mass cost by unsteady blowing is only 63.7% of that by steady blowing per rotation revolution. The results show that unsteady blowing can effectively reduce BVI noise with lower cost and less thrust loss.

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