CAA Prediction of Rotor-Stator Interaction Using Synthetic Turbulence: Application to a Low-Noise Serrated OGV

Reboul, G.; Cader, Adil; Polacsek, Cyril; Garrec, Thomas Le; Barrier, Raphaël; Nasr, Nabil Ben

doi:10.2514/6.2017-3714

Cited by 11 publications

(11 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Another key parameter is the choice of a convenient ratio h s /λ s . Although the acoustic benefit could be improved by increasing h s , a practical limitation is required to avoid a noticeable loss of aerodynamic performance for industrial applications, as discussed by Reboul et al 7 Hence, setting h s /λ s = 1 gives θ s = 76°, which can be considered as a reasonable value close to the optimum design according to Narayanan et al 4 Another important result highlighted by Chaitanya et al 5 is that the sound power attenuation, ∆PWL, that can be achieved by a single-wavelength serrated LE, is approximately proportional to the Strouhal number, S th = fh s /U, at the optimum serration wavelength, where U is the freestream velocity and f is the frequency. The following empirical law was proposed:…”

Section: Background On Acoustic Performances Of Leading Edge Serrationsmentioning

confidence: 99%

See 1 more Smart Citation

Aeroacoustic design and broadband noise predictions of a fan stage with serrated outlet guide vanes

et al. 2020

View full text Add to dashboard Cite

This work, realized in the framework of the European project TurboNoiseBB, presents an advanced aeroacoustic design methodology of Outlet Guide Vanes (OGVs) with leading edge serrations, including details on their broadband noise and aerodynamic performance. The serrated OGV corresponds to a modified stator from an aero-engine fan stage tested at the AneCom Aerotest's facility (Germany). Sinusoidal leading edge patterns with varying amplitude and wavelength along the span are designed in collaboration with Safran Aircraft Engines. Serrations are adjusted to account for the turbulence characteristics provided by Reynolds-Averaged Navier-Stokes (RANS) calculations. Optimal parameters are found using simple design rules discussed in the paper. Down selection of serrated OGV designs (patent pending) are conducted through a RANS control of aerodynamic performances and in accordance with industrial specifications, ensuring acceptable penalties on the loss coefficient and isentropic efficiency. Broadband noise simulations are performed using a computational aeroacoustic (CAA) code that solves the linearized Euler equations with a synthetic turbulence model. Additionally, the acoustic response of the serrated leading edge airfoils is also estimated using the most relevant analytical formulation in the literature, based on the Wiener-Hopf technique. Numerical predictions at approach conditions are compared to available experimental measurements (on the untreated baseline case) and analytical Amiet-based and Wiener-Hopf solutions, showing a satisfactory agreement in the sound power spectrum in the bypass duct. Finally, the acoustic performances estimated at the design stage are numerically assessed by both CAA and Wiener-Hopf methods, providing around 2.5 dB and 3.5 dB reduction on the overall power level, respectively.

show abstract

Section: Background On Acoustic Performances Of Leading Edge Serrationsmentioning

confidence: 99%

“…In the past ten years, turbulence interaction noise reduction using leading edge (LE) serrations has been extensively studied. [1][2][3][4][5][6][7][8][9][10] . One of the first studies related to the design and manufacture of airfoils with LE serrations was performed by ONERA (Refs.…”

Section: Introductionmentioning

confidence: 99%

Aeroacoustic design and broadband noise predictions of a fan stage with serrated outlet guide vanes

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Three-dimensional approaches are advantageous as they can consider complex, 3D flows and enable the realization of fully anisotropic turbulence as shown by Gea-Aguilera et al 9 They can also consider vane geometries that change significantly in the spanwise direction, e. g. due to leading edge serrations as demonstrated in several works. 10,11,12,13 However, 3D methods tend to be expensive. Possible strategies aimed at mitigating simulation times include:…”

Section: Introductionmentioning

confidence: 99%

“…• The simulation domain can be limited to one or a few stator channels. The implications are discussed by Reboul et al 13 • The simulation domain can be limited to a spanwise section as was the case for Clair et al's 10 study of leading edge serrations.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Assessment of a 2D Synthetic Turbulence Method for Predicting the ACAT1 Fan's Broadband Noise

Kissner

Guérin

Behn

2019

25th AIAA/CEAS Aeroacoustics Conference

View full text Add to dashboard Cite

Fan broadband noise, particularly rotor-stator-interaction noise, is an important noise mechanism in modern aircraft engines. However, its prediction is not trivial. Applied approaches range from fast but simplified analytical approaches to computationally demanding turbulence scale-resolving simulations. RANS-informed synthetic turbulence methods present a promising compromise between accuracy and cost. Two-dimensional simulations on a single streamline are especially attractive as they can be easily computed on conventional computers. While a good agreement with NASA SDT experimental data could be shown in the past, it can be questioned how representative a 2D simulation at an arbitrarily chosen streamline position can truly be since the flow and turbulence in the interstage region is highly dependent on the fan geometry and its operating conditions. In this paper, the authors propose a new, 3D-equivalent approach for setting up a 2D synthetic turbulence simulation. The results are compared to approaches that were applied for past investigations. In addition, a detailed comparison to the comprehensive, acoustic test data for the AneCom AeroTest 1 (ACAT1) transonic fan is shown. The good agreement between numerical and experimental data proves that a fast, two-dimensional synthetic turbulence method is indeed capable of accurate fan broadband noise predictions.

show abstract

Exploring the suppression mechanism of wind buffeting noise with bionic structures featuring leading-edge serrations and surface ridges

Cao

Zhang

et al. 2023

Journal of Low Frequency Noise, Vibration and Active Control

View full text Add to dashboard Cite

The aim of this study is to investigate the effectiveness and mechanism of wind buffeting noise suppression using a new bionic structure inspired by the quiet flight of owls. Firstly, the new bionic schemes based on NACA0012 wing with two sinusoidal leading-edge serrations and one straight leading-edge curve are used in a cavity after verifying the simulation. Then, the results of the three bionic schemes are compared and analyzed. It is found that the schemes with leading-edge serrations and surface ridges can suppress wind buffeting noise effectively. In particular, the sinusoidal scheme with a wavelength λ = 0.24 c (chord length c) can significantly reduce resonance energies above 21 dB over a wide range of speeds. Furthermore, the study reveals that in the bionic scheme, only the negative pressure core moves in the opening and hits the trailing edge, which reduces the pressure fluctuation in the cavity. The boundary layer thickness (BLT) also fluctuates in span under the influence of the leading-edge serration and the surface ridge, which is favorable for suppressing wind buffeting noise. However, the suppression effect is not solely related to the fluctuation of BLT in the span at the trailing edge but is also influenced by the minimum BLT at this point. Therefore, if the BLT has a certain intensity fluctuation in the span, and the minimum BLT at the trailing edge is close to that of the smooth airfoil scheme, the noise suppression effect is significant.

show abstract

CAA Prediction of Rotor-Stator Interaction Using Synthetic Turbulence: Application to a Low-Noise Serrated OGV

Cited by 11 publications

References 29 publications

Aeroacoustic design and broadband noise predictions of a fan stage with serrated outlet guide vanes

Aeroacoustic design and broadband noise predictions of a fan stage with serrated outlet guide vanes

Assessment of a 2D Synthetic Turbulence Method for Predicting the ACAT1 Fan's Broadband Noise

Exploring the suppression mechanism of wind buffeting noise with bionic structures featuring leading-edge serrations and surface ridges

Contact Info

Product

Resources

About