Effect of pressure gradients on turbulent boundary layer noise and wall-pressure fluctuations

Cohen, Elie; Gloerfelt, Xavier

doi:10.2514/6.2015-3117

Cited by 11 publications

(3 citation statements)

References 22 publications

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“…The forms of the pressure fluctuation spectrum are consistent with the results of studies by other authors [17][18][19] and semiempirical models, describing the Robertson [20]/Cockburn and Robertson models [21], respectively, and the Efimtsov 1 [22] and 2 [23]/Rackle and Weston models [24]. Furthermore, the absence of tonal components in the pressure fluctuation spectrum indicates the dominance of the pressure fluctuation field over the engine's acoustic radiation.…”

Section: Spectrum Of Pressure Fluctuation Levels In Cruising Flight Modesupporting

confidence: 88%

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Analysis of the Sound Field Structure in the Cabin of the RRJ-95NEW-100 Prototype Aircraft

Lavrov¹,

Moshkov

Strelets

2023

Aerospace

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The results of in-flight experiments to determine the structure of the sound field in the cabin and pressure fluctuation fields on the surface of the fuselage of the RRJ-95NEW-100 prototype aircraft are presented here. Wall pressure fluctuation spectrums are obtained for three zones of measuring windows (forward, center, and rear fuselage) in cruising flight mode. The effect of the jet on the pressure fluctuation levels in the tail fuselage is considered. For an aircraft without an interior, the contribution of the main sources to the total intensity calculated through A-weighted overall sound pressure levels is determined. It has been determined that the main noise sources in the cabin of the RRJ-95NEW-100 prototype aircraft in cruising flight mode are pressure fluctuation fields on the fuselage surface (turbulent boundary layer noise) and the air conditioning system. The ratio between the sources varies along the length of the cabin.

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Section: Spectrum Of Pressure Fluctuation Levels In Cruising Flight Modesupporting

confidence: 88%

“…The tonal components of engine noise do not stand out against the background of the broadband component of pressure fluctuation fields. The results of the author's research are consistent with the experiments of other authors [17][18][19]27].…”

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confidence: 89%

Analysis of the Sound Field Structure in the Cabin of the RRJ-95NEW-100 Prototype Aircraft

Lavrov¹,

Moshkov

Strelets

2023

Aerospace

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“…Consequently, the radiation efficiency is weak, explaining the great care required to obtain the radiated field. Another study by Cohen & Gloerfelt (2015) investigated the effect of both a favourable and an adverse pressure gradient on the wall-pressure signature. These simulations are analysed in the present work, and will be compared and put into perspective with the results of available databases.…”

Section: Introductionmentioning

confidence: 99%

Influence of pressure gradients on wall pressure beneath a turbulent boundary layer

Cohen

Gloerfelt

2018

J. Fluid Mech.

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This study investigates the effects of a pressure gradient on the wall pressure beneath equilibrium turbulent boundary layers. Excitation of the walls of a vehicle by turbulent boundary layers indeed constitutes a major source of interior noise and it is necessary to take into account the presence of a pressure gradient to represent the effect of the curvature of the walls. With this aim, large-eddy simulations of turbulent boundary layers in the presence of both mild adverse and mild favourable pressure gradients are carried out by solving the compressible Navier–Stokes equations. This method provides both the aeroacoustic contribution and the hydrodynamic wall-pressure fluctuations. A critical comparison with existing databases, including recent measurements, is conducted to assess the influence of a free stream pressure gradient. The analyses of wall-pressure spectral densities show an increase in the low-frequency content from adverse to favourable conditions, yielding higher integrated levels of pressure fluctuations scaled by the wall shear stress. This is accompanied by a steeper decay rate in the medium-frequency portion for adverse pressure gradients. No significant difference is found for the mean convection velocity. Frequency–wavenumber spectra including the subconvective region are presented for the first time in the presence of a pressure gradient. A scaling law for the convective ridge is proposed, and the acoustic domain is captured by the simulations. Direct acoustic emissions have similar features in all gradient cases, even if slightly higher levels are noted for boundary layers subjected to an adverse gradient.

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Problems of a Supersonic Business Aircraft Design with Regard to Cabin Noise Requirements

Moshkov¹,

Strelets²

2023

Springer Aerospace Technology

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Effect of pressure gradients on turbulent boundary layer noise and wall-pressure fluctuations

Cited by 11 publications

References 22 publications

Analysis of the Sound Field Structure in the Cabin of the RRJ-95NEW-100 Prototype Aircraft

Analysis of the Sound Field Structure in the Cabin of the RRJ-95NEW-100 Prototype Aircraft

Influence of pressure gradients on wall pressure beneath a turbulent boundary layer

Problems of a Supersonic Business Aircraft Design with Regard to Cabin Noise Requirements

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