Predicting the rotor-stator interaction acoustics of a ducted fan engine

Teszka, Robert; Christopher, L Rumsey; Gary, G Podboy; Dunn, M. H.

doi:10.2514/6.2001-664

Cited by 10 publications

(4 citation statements)

References 9 publications

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“…In this case however, theses sources are spinning to represent the noise due to the rotating blades in the engine. In particular, we are trying to represent the (6,1) mode, which is of particular interest due to the results of Biedron and Rumsey [24]. The results are shown in Figure 11, including aft radiation.…”

Section: Fore and Aft Radiation From A Generic Ductmentioning

confidence: 99%

A nonconservative nonlinear flowfield splitting method for 3-D unsteady fluid dynamics

Long¹

2000

6th Aeroacoustics Conference and Exhibit

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This paper describes a new way to write and solve the governing equations of fluid dynamics that is very well suited to aeroacoustics problems. The flow field variables are split into a mean and a fluctuating part, and then inserted into the governing equations. If the mean flowfield satisfies the steady-state governing equations, then the resulting equations can be written in a very convenient form. These equations are then solved using a method that is second or fourth order accurate in space and time, on a Cartesian grid. Several aeroacoustic benchmark problems are solved, some duct propagation problems are presented, and a longrange scattering problem is solved. The code is written in Fortran-90 using the Message Passing Interface (MPI), and performance results are presented for a cluster of workstations. This paper describes a method that is designed to take advantage of the best features of existing CFD and _______________________________________

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Section: Fore and Aft Radiation From A Generic Ductmentioning

confidence: 99%

A nonconservative nonlinear flowfield splitting method for 3-D unsteady fluid dynamics

Long¹

2000

6th Aeroacoustics Conference and Exhibit

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“…[10][11][12][13][14] Full fan configuration prediction codes often require: • blade acoustic source definition • linearizing the flow equations • and the use of linear theory for acoustically post-processing RANS solutions [15][16][17] A recent full fan configuration based on first principles only (solves thin-layer, Navier-Stokes equations) was unable to successfully simulate the generation and propagation of acoustic signals due to its inherent dissipation and dispersion. 18 Building on these past efforts, NASA Glenn Research Center has developed a Broadband Analysis Stator Simulator (BASS) code 19 that for the first time ever successfully simulates the full nonlinear, time-accurate, acoustic response of an unrolled section (2D cascade) at a radial location of a modern stator vane configuration. Our simulation assumes inviscid and ideal flow, but it solves for the entire flow field using a truly time-accurate methodology that enables the simultaneous calculation of the entire range of frequency response up to at least three times the blade passage frequency (BPF).…”

Section: Introductionmentioning

confidence: 99%

Simulating nonlinear stator noise for active control

Dyson¹,

Hixon²,

Nallasamy³

et al. 2004

Noise Control Eng. J.

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The intent of this work is to demonstrate that nonlinear effects on realistic geometries can be a tool for fan noise reduction. Noise produced from a rotating blade row's convected vortical gusts impinging upon a stationary blade row (stator) was simulated using novel high order numerical techniques. Results from this simulation indicate nonlinear resonance in a blade passage may be used to reduce turbofan engine noise by exciting high-frequency destructive modes with a more easily controlled low-frequency on-blade actuator. This technique of noise reduction is particularly attractive in a duct when cut-off modes are chosen as the base actuator frequency. A combination of large amplitude actuator produced cut-off modes with their corresponding nonlinear harmonic destructive interference patterns is a potential new area of active noise control research.

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“…CANARI provides the inputs required for acoustics. As commonly adopted by many authors from the aeroacoustic community, [7][8][9][10][11][12][13][14][15][16] a modal approach based on the expansion of CFD perturbations over incoming and outgoing Fourier-Bessel harmonics is used to match the CFD and CAA domains, assuming a uniform mean flow and annular geometry in the matching region. The main originality here is that the outgoing modes are re-generated in terms of equivalent monopoles, to be entered as source inputs in the CAA, rather than directly use the pressure mode profile as a boundary condition.…”

Section: Introductionmentioning

confidence: 99%

“…Although most advanced fan propagation/radiation solvers are based on PE, 12 FEM (potential flow), 9,16 Euler/Kirchhoff 8,15 or Euler/FW-H, 11,14 acoustic propagation/ radiation is simultaneously obtained here using BEM. Such an approach is of course rather restrictive in terms of flow conditions (convection effects have to be neglected), but it is faster and easily implemented (particularly for axi-symmetrical problems), and probably the best suited to the case studied in this work.…”

Section: Introductionmentioning

confidence: 99%

Fan Interaction Noise Predictions Using RANS-BEM Coupling

Polacsek

Burguburu²

2005

International Journal of Aeroacoustics

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A source-to-far-field computation procedure aiming at predicting the noise generated by rotor-stator fan interactions and inlet noise radiation is presented here. It is applied to the NLR turbofan model, tested in DNW-LLF anechoic chamber under the framework of DUCAT project. The unsteady aerodynamic input for the acoustic computation is obtained using a 3D RANS code, CANARI, developed at ONERA for turbomachinery applications. The CFD solutions are coupled, using a modal expansion approach, to a BEM code, solving the Helmholtz equation in an arbitrary bounded space. A single interacting cut-on mode amplitude is either directly deduced from experiment or provided by post-processing the CFD data. With this approach, the predicted noise radiation can be related to the directivity patterns measured at several axial positions upstream of the turbofan inlet. A fairly good agreement is found using both experimental and CFD input data.

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Predicting the rotor-stator interaction acoustics of a ducted fan engine

Cited by 10 publications

References 9 publications

A nonconservative nonlinear flowfield splitting method for 3-D unsteady fluid dynamics

A nonconservative nonlinear flowfield splitting method for 3-D unsteady fluid dynamics

Simulating nonlinear stator noise for active control

Fan Interaction Noise Predictions Using RANS-BEM Coupling

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