Fan Broadband Interaction Noise Modeling

Grace, Sheryl M.; Wixom, Andrew S.; Winkler, Julian; Sondak, Douglas L.; Logue, Michaela M.

doi:10.2514/6.2012-2269

Cited by 14 publications

(16 citation statements)

References 3 publications

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“…It was shown that when only the average passage value is used, the roll off above 10 kHz is increased. 4 Including the variation in the turbulence intensity may make the broadband vane response also roll off more slowly and thus be in better agreement with the data. Since the upwash velocity is most easily defined in the rotor frame (as above), rather than carry out the integration in the stator frame, we will use the following transformation to move all quantities to the rotor frame.…”

Section: Experimental Datamentioning

confidence: 74%

“…First the response of the fan exit guide vane (FEGV) is computed and then the broadband sound is calculated. [1][2][3][4] Comparisons of the final duct acoustic power predicted by these various methods have been compared against each other and against experimental findings in the past. 5 It has been shown that different modeling assumptions lead to slightly different predictions.…”

Section: Introductionmentioning

confidence: 99%

“…In this paper, results from the simulation of the broadband response of a fan exit guide vane to the ingested turbulence via the RSI method 1,4 will be compared to measurements. The experimental data utilized here are taken from the Source Diagnostic Test (SDT) database.…”

Section: Introductionmentioning

confidence: 99%

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Prediction of broadband fan exit guide vane response

Grace

Forsyth

2013

19th AIAA/CEAS Aeroacoustics Conference

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The ability to predict the broadband fan exit guide vane response to interaction with wake turbulence using a low-order method is investigated. The RSI method is used to simulate the response of the low-count vanes in the Source Diagnostic Test. The predicted pressure spectrum is compared to that measured experimentally. The predicted spectrum of the broadband vane response at all points on the vane is similar to the final acoustic spectrum, both measured and predicted, that has been presented previously in the literature. However, this means that the simulated results do not capture spectral features above 20 kHz that are present in the experimental data. The physical source of the additional spectral features must still be identified. The simulated results match the data under 20 kHz fairly well near the midspan, but underpredict the levels for frequencies below 4 kHz at positions near the hub and the tip.

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Section: Experimental Datamentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

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Prediction of broadband fan exit guide vane response

Grace

Forsyth

2013

19th AIAA/CEAS Aeroacoustics Conference

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“…Many low-order methods for simulating broadband interaction noise downstream of a fan stage in a turbofan engine have emerged recently [1][2][3][4] . These methods all rely on a simplified model of the fan exit guide vane (FEGV) that replaces the real vane with a flat vane.…”

Section: Introductionmentioning

confidence: 99%

Investigation of methods for including vane geometry in predictions of fan broadband noise

Grace

Villafranco

Wixom

2016

22nd AIAA/CEAS Aeroacoustics Conference

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Two methods for increasing the geometric fidelity of a fan-stage, broadband, interaction-noise model are investigated. The increase in fidelity is sought in order to eliminate the dependence on stagger selection that exists when vanes are modeled as flat plates. First, a blade-vortex interaction (BVI) technique is considered for obtaining a subsonic, 2D, unsteady, real-geometry cascade response that can be readily incorporated into an existing low-order broadband model. A description of the overall method and results from the development of the cascade-BVI are presented. Second, a method for utilizing a linearized Euler calculation that has been presented in the literature previously is reviewed and discussed. Preliminary findings from an attempt to utilize LINFLUX as the linearized Euler solver in the broadband model are described.

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“…Rotor-stator interaction (RSI) by Nallasamy and Envia [21] is based on Ventres et al's [16] 2-D method. (The most recent RSI results can be found in [22].) Cheong et al [23] developed a broadband model based on LINSUB [17].…”

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confidence: 99%

Investigation of Fan-Wake/Outlet-Guide-Vane Interaction Broadband Noise

et al. 2015

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Fan-wake/outlet-guide-vane interaction broadband noise in turbofan jet engines is studied. The mechanism and some issues are first discussed using a two-dimensional gust-prediction model. An oblique gust-prediction model is then developed. Quasi-three-dimensional unsteady lift is calculated using a two-dimensional equivalence method. It is coupled with annular duct modes to obtain the sound power spectrum density. Spanwise turbulence integral length scales and their impact on power spectrum density predictions are investigated. A spanwise integration limit suitable for the complete frequency range is proposed. The model is validated using the NASA Source Diagnostic Test data. Sound power scaling with vane count B is examined. If solidity is maintained, the cascade response does not converge on the single-airfoil response, even for low vane counts. The sound power varies inversely with B at low frequency; it scales with B at very high frequency. The power spectrum density trend with the fan tip Mach number M T is also identified. It scales with M 5 T if turbulence intensity in the fan wake scales "ideally" with M T. At offdesign conditions, fan wakes are not ideal; therefore, different speed trends apply. M 3.3 T scaling is found to best fit the Source Diagnostic Test data and the prediction.

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Fan Broadband Interaction Noise Modeling

Cited by 14 publications

References 3 publications

Prediction of broadband fan exit guide vane response

Prediction of broadband fan exit guide vane response

Investigation of methods for including vane geometry in predictions of fan broadband noise

Investigation of Fan-Wake/Outlet-Guide-Vane Interaction Broadband Noise

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