Simplified Approach of Jet Aerodynamics with a View to Acoustics

Varnier, Jean; Koudriavtsev, V. V.; Сафронов, А. В.

doi:10.2514/1.5087

Cited by 13 publications

(5 citation statements)

References 7 publications

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“…Semi-empirical noise source and propagation models have been developed in parallel 15 but their ability to predict realistic installation effects remains poor. On the contrary, numerical simulations of the Navier-Stokes equations give access to detailed flow information on increasingly complex configurations.…”

Section: Introductionmentioning

confidence: 99%

Accurate simulation of the noise generated by a hot supersonic jet including turbulence tripping and nonlinear acoustic propagation

et al. 2019

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A procedure to accurately simulate a free hot supersonic jet and its associated noise, which uses simultaneously a turbulence tripping method and a two-way coupling between a flow solver and a nonlinear acoustic solver, is proposed in this study. A Mach 3.1 overexpanded hot jet is computed via a large-eddy simulation by solving the filtered Navier-Stokes equations with a finite volume method on unstructured grids. The resulting noise is propagated in the far field by solving the full Euler equations with a high-order discontinuous Galerkin method on unstructured grids. The full convergent-divergent nozzle is explicitly included in the computational domain thanks to the unstructured flow solver. Both a refined grid and a geometrical boundary layer tripping in the convergent are used to get highly disturbed turbulent conditions at the nozzle lips. The flow field appears to agree with the expected turbulence behavior and the available experimental data. The jet development shows significant improvement compared to similar past simulations. The far field acoustic levels are finely recovered at most of observation angles. An analysis of the acoustic near and far fields is then performed. The studied conditions lead to strong shock-associated noise and Mach wave emission. The spatio-frequency and azimuthal content of the acoustic field is described in order to identify the main noise properties. A particular noise component, different from screech tones and radiating upstream like Mach waves, is highlighted. Nonlinear propagation effects are finally quantified through specific metrics. They are found significant in both the near and the far fields which justifies the use of a nonlinear acoustic solver.

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Section: Introductionmentioning

confidence: 99%

Accurate simulation of the noise generated by a hot supersonic jet including turbulence tripping and nonlinear acoustic propagation

et al. 2019

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“…It is an improvement of the Eldred Standard model, based on heuristic assumptions and scaling laws, properly tuned against experimental data from different rocket engines [8][9][10][11]. In this simple model, in order to determine a realistic equivalent noise source, several parameters, such as the vehicle geometry or launch pad configurations, have to be taken into account.…”

Section: Introductionmentioning

confidence: 99%

Integrated Aero–Vibroacoustics: The Design Verification Process of Vega-C Launcher

et al. 2018

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Abstract:The verification of a space launcher at the design level is a complex issue because of (i) the lack of a detailed modeling capability of the acoustic pressure produced by the rocket; and (ii) the difficulties in applying deterministic methods to the large-scale metallic structures. In this paper, an innovative integrated design verification process is described, based on the bridging between a new semiempirical jet noise model and a hybrid finite-element method/statistical energy analysis (FEM/SEA) approach for calculating the acceleration produced at the payload and equipment level within the structure, vibrating under the external acoustic forcing field. The result is a verification method allowing for accurate prediction of the vibroacoustics in the launcher interior, using limited computational resources and without resorting to computational fluid dynamics (CFD) data. Some examples concerning the Vega-C launcher design are shown.

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“…The main contributions include the noise generated by the free part of the jet, the impinging region inside the flame trench, the noise emitted at the end of the flame duct and the reflected and diffracted noise on the launch pad. In addition to various experimental studies [5] which have led to significant noise reduction on launch pads [6], semi-empirical jet noise models based on the Lighthill's theory have been formulated [7] and improved [8][9][10] but they are often unsuitable to deal with such realistic space applications. More recently, the development of large-eddy simulation (LES) allowed accurate simulations of hot supersonic jets [11][12][13][14][15], even for increasingly complex configurations as performed with realistic launch pad geometries by Fujii et al [16] or Tsutsumi et al [17].…”

Section: Introductionmentioning

confidence: 99%

Assessment of a Two-Way Coupling Methodology Between a Flow and a High-Order Nonlinear Acoustic Unstructured Solvers

Langenais

Vincent

Peyret

et al. 2018

Flow Turbulence Combust

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A two-way coupling on unstructured meshes between a flow and a high-order acoustic solvers for jet noise prediction is considered. The flow simulation aims at generating acoustic sources in the near field while the acoustic simulation solves the full Euler equations, thanks to a discontinuous Galerkin method, in order to take into account nonlinear acoustic propagation effects. This methodology is firstly validated on academic cases involving nonlinear sound propagation, shock waves and convection of aerodynamic perturbations. The results are compared to analytical solutions and direct computations. A good behaviour of the coupling is found regarding the targeted space applications. An application on a launch pad model is then simulated to demonstrate the robustness and reliability of the present approach.

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Simplified Approach of Jet Aerodynamics with a View to Acoustics

Cited by 13 publications

References 7 publications

Accurate simulation of the noise generated by a hot supersonic jet including turbulence tripping and nonlinear acoustic propagation

Accurate simulation of the noise generated by a hot supersonic jet including turbulence tripping and nonlinear acoustic propagation

Integrated Aero–Vibroacoustics: The Design Verification Process of Vega-C Launcher

Assessment of a Two-Way Coupling Methodology Between a Flow and a High-Order Nonlinear Acoustic Unstructured Solvers

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