Computational aeroacoustics applications based on a discontinuous Galerkin method

SUMMARY An efficient discontinuous Galerkin formulation is applied to the solution of the linearized Euler equations and the acoustic perturbation equations for the simulation of aeroacoustic propagation in two‐dimensional and axisymmetric problems, with triangular and quadrilateral elements. To improve computational efficiency, a new strategy of variable interpolation order is proposed in addition to a quadrature‐free approach and parallel implementation. Moreover, an accurate wall boundary condition is formulated on the basis of the solution of the Riemann problem for a reflective wall. Time discretization is based on a low dissipation formulation of a fourth‐order, low storage Runge–Kutta scheme. Along the far‐field boundaries a perfectly matched layer boundary condition is used. For the far‐field computations, the integral formulation of Ffowcs Williams and Hawkings is coupled with the near‐field solver. The efficiency and accuracy of the proposed variable order formulation is assessed for realistic geometries, namely sound propagation around a high‐lift airfoil and the Munt problem. Copyright © 2011 John Wiley & Sons, Ltd.

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“…Similar analysis can be found in . Examples of applications of the DGM for the solution of aeroacoustic problems are reported, among others, in .…”

Section: Introductionsupporting

confidence: 72%

An efficient discontinuous Galerkin method for aeroacoustic propagation

Rinaldi

Iob

Arina

2011

Numerical Methods in Fluids

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“…The ONERA unstructured computational aeroacoustics (CAA) code SPACE 48,49 is used in the zone Z2. The full Euler equations are solved through a nodal discontinuous Galerkin method using high-order polynomial elements without order limit.…”

Section: Acoustic Computationmentioning

confidence: 99%

“…It has been established that high-order methods for aeroacoustic problems are beneficial in terms of cost/accuracy ratio. 50 According to Delorme et al, 48 a PPW = 14 discretization is required at the 2 nd spatial order and only PPW = 3 at the 4 th order for an ideal case of wave propagation. The cut-off Strouhal number is linked to PPW via equation (1) and K is set to 1.2 as previously.…”

Section: Acoustic Computationmentioning

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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“…Yong Cho [2] proposed a computational method for the aero-acoustic modeling of the cross flow fan at low frequency, the reflection is ignored. Finite element method could be applied to compute complex wall problems using unstructured mesh , but it could not solve LEE due to lacking of some models [3]. Marc Bernacki [4] used discontinuous Galerkin unstructuredmesh solvers to simulate noise propagation around the aircraft, but the primary functions are complex and huge computation resource is needed.…”

Section: Introductionmentioning

confidence: 99%

Aerodynamic noise propagation simulation using immersed boundary method and finite volume optimized prefactored compact scheme

Liu

Wu²

2008

J. Therm. Sci.

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Based on the immersed boundary method (IBM) and the finite volume optimized pre-factored compact (FVOPC) scheme, a numerical simulation of noise propagation inside and outside the casing of a cross flow fan is established. The unsteady linearized Euler equations are solved to directly simulate the aero-acoustic field . In order to validate the FVOPC scheme, a simulation case: one dimensional linear wave propagation problem is carried out using FVOPC scheme, DRP scheme and HOC scheme. The result of FVOPC is in good agreement with the analytic solution and it is better than the results of DRP and HOC schemes. the FVOPC is less dispersion and dissipation than DRP and HOC schemes. Then, numerical simulation of noise propagation problems is performed. The noise field of 36 compact rotating noise sources is obtained with the rotating velocity of 1000r/min. The PML absorbing boundary condition is applied to the sound far field boundary condition for depressing the numerical reflection. Wall boundary condition is applied to the casing. The results show that there are reflections on the casing wall and sound wave interference in the field. The FVOPC with the IBM is suitable for noise propagation problems under the complex geometries for depressing the dispersion and dissipation, and also keeping the high order precision.

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Computational aeroacoustics applications based on a discontinuous Galerkin method

Cited by 37 publications

References 7 publications

An efficient discontinuous Galerkin method for aeroacoustic propagation

An efficient discontinuous Galerkin method for aeroacoustic propagation

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

Aerodynamic noise propagation simulation using immersed boundary method and finite volume optimized prefactored compact scheme

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