Gust acoustic response of a single airfoil using the space-time CE/SE method

Scott, James R.; Wang, X. Y.; Chang, Sin-Chung; Himansu, Ananda; Jorgenson, Philip C. E.

doi:10.2514/6.2002-801

Cited by 4 publications

(4 citation statements)

References 6 publications

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“…Along with the GUST3D code, the results are from the PFC6 code of Hixon et al [14][15][16], the CE/SE code of Wang et al [17,18,4], the DSEM code of Rasetarinera et al [19,20] …”

Section: Benchmark Resultsmentioning

confidence: 99%

Benchmark Solutions for Computational Aeroacoustics (CAA) Code Validation

Scott

2004

Noise Control and Acoustics

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NASA has conducted a series of Computational Aeroacoustics (CAA) Workshops on Benchmark Problems to develop a set of realistic CAA problems that can be used for code validation. In the Third (1999) and Fourth (2003) Workshops, the single airfoil gust response problem, with real geometry effects, was included as one of the benchmark problems. Respondents were asked to calculate the airfoil RMS pressure and far-field acoustic intensity for different airfoil geometries and a wide range of gust frequencies. This paper presents the validated solutions that have been obtained to the benchmark problem, and in addition, compares them with classical flat plate results. It is seen that airfoil geometry has a strong effect on the airfoil unsteady pressure, and a significant effect on the far-field acoustic intensity. Those parts of the benchmark problem that have not yet been adequately solved are identified and presented as a challenge to the CAA research community.

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“…Along with the GUST3D code, the results are from the PFC6 code of Hixon et al [14][15][16], the CE/SE code of Wang et al [17,18,4], the DSEM code of Rasetarinera et al [19,20] …”

Section: Benchmark Resultsmentioning

confidence: 99%

Benchmark Solutions for Computational Aeroacoustics (CAA) Code Validation

Scott

2004

Noise Control and Acoustics

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“…For gusts with wavenumber k 1 ¼ k 2 ¼ 1, time-averaged pressure (hp wall i) and root-mean-squared (RMS) pressure, ; distributions on the airfoil surface are presented in Fig. 2, compared with benchmark reference values from Wang et al 42 There is a very small difference near the peak between current simulation results and reference data, about 0.25% at the peak of mean pressure and 5.3% for RMS pressure. Above all, a very good agreement is obtained.…”

Section: Cflmentioning

confidence: 92%

“…They show a good agreement with the reference data. 42 There is some fluctuation for the smallest domain size (case 3). This may be caused by the fact that the points on the circle with a four-chord length radius are very close to the boundary of the sponge layer.…”

Section: Cflmentioning

confidence: 98%

“…Gust-airfoil interaction noise is studied widely by analytical methods [9][10][11] and numerical simulations. 12,13 Sears 14 was the first to develop an analytical model to study the lift and moment of an airfoil interacting with a harmonic vortical gust. Amiet 15 extended Sears's model by considering the noise generation of turbulence interacting with an infinite thin flat plate, which became the basis of analytical models to predict turbulence-airfoil interaction noise.…”

Section: Introductionmentioning

confidence: 99%

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Variations with Mach number for gust–airfoil interaction noise

et al. 2023

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The interaction of turbulence with airfoil is an important noise source in many engineering fields, including helicopters, turbofan, and contra-rotating open rotor engines, where turbulence generated in the wake of upstream blades interacts with the leading edge of downstream blades and produces aerodynamic noise. One approach to study turbulence-airfoil interaction noise is to model the oncoming turbulence as harmonic gusts. A compact noise source produces a dipole-like sound directivity pattern. However, when the acoustic wavelength is much smaller than the airfoil chord length, the airfoil needs to be treated as a non-compact source, and the gust-airfoil interaction becomes more complicated and results in multiple lobes generated in the radiated sound directivity. Capturing the short acoustic wavelength is a challenge for numerical simulations. In this work, simulations are performed for gust-airfoil interaction at different Mach numbers, using a high-fidelity direct Computational AeroAcoustic (CAA) approach based on a spectral/hp element method, verified by a CAA benchmark case. It is found that the squared sound pressure varies approximately as the 5th power of Mach number, which changes slightly with the observer location. This scaling law can give a better sound prediction than the flat-plate theory for thicker airfoils. Besides, another prediction method, based on the flat-plate theory and CAA simulation, has been proposed to give better predictions than the scaling law for thicker airfoils.

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