Hybrid numerical model for acoustic propagation through sheared flows

Hamiche, Karim; Bras, Sophie Le; Gabard, Gwénaël; Bériot, Hadrien

doi:10.1016/j.jsv.2019.114951

Cited by 5 publications

(7 citation statements)

References 33 publications

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“…This is consistent with the comparison for three-dimensional calculations reported by Hamiche et al. (2019).…”

Section: Applicationssupporting

confidence: 93%

“…For a given mesh and accuracy, the use of the LEE leads to an increase by a factor 7 in the execution time and by a factor 15 in the memory requirements of the linear solver when compared to Pierce's or Goldstein's equations. This is consistent with the comparison for three-dimensional calculations reported by Hamiche et al (2019).…”

Section: Free-field Propagationsupporting

confidence: 93%

“…To illustrate this, two additional test cases are considered, namely the sound radiated by a source in a hot jet, and the sound produced by a point source in a duct with a hot sheared flow. The solutions from the direct problems are also compared to reference solutions obtained with the linearised Euler equations solved using the same high-order finite element method (Hamiche et al 2019). The aim is to assess quantitatively the impact of the simplifications involved in Pierce's and Goldstein's operators when mean temperature gradients are present or when the mean flow is not homentropic.…”

Section: Propagation In Sheared Non-isothermal Flowsmentioning

confidence: 99%

“…Various scalar linearised acoustic operators can be considered to reduce the computational costs. For instance, the well-known linearised potential equation proposed by Blokhintzev (1946) and Goldstein (1978) constitutes an efficient way to model sound propagation in potential mean flows (Hamiche et al 2019). It is written for the acoustic velocity potential assuming that both vorticity and entropy effects are excluded from the mean flow and the linear perturbations.…”

Section: Introductionmentioning

confidence: 99%

“…For this purpose, the boundary element method has been used to solve the classical Helmholtz equation (Schram 2009;Chaillat et al 2022) or the convected Helmholtz equation (Hu, Guo & Jones 2005). In the present work, the direct and adjoint problems are solved in the frequency domain using a high-order finite element method that has been applied previously to solve propagation problems based on the Helmholtz equation (Bériot, Prinn & Gabard 2016), Goldstein's equation (Gabard et al 2018) and the LEE (Hamiche et al 2019).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Direct and adjoint problems for sound propagation in non-uniform flows with lined and vibrating surfaces

Bras

Gabard²,

Bériot³

2022

J. Fluid Mech.

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This paper presents a systematic analysis of direct and adjoint problems for sound propagation with flow. Two scalar propagation operators are considered: the linearised potential equation from Goldstein, and Pierce's equation based on a high-frequency approximation. For both models, the analysis involves compressible base flows, volume sources and surfaces that can be vibrating and/or acoustically lined (using the Myers impedance condition), as well as far-field radiation boundaries. For both models, the direct problems are fully described and adjoint problems are formulated to define tailored Green's functions. These Green's functions are devised to provide an explicit link between the direct problem solutions and the source terms. These adjoint problems and tailored Green's functions are particularly useful and efficient for source localisation problems, or when stochastic distributed sources are involved. The present analysis yields a number of new results, including the adjoint Myers condition for the linearised potential equation, as well as the formulation of the direct and adjoint Myers condition for Pierce's equation. It is also shown how the adjoint problems can be recast in forms that are readily solved using existing simulation tools for the direct problems. Results presented in this paper are obtained using a high-order finite element method. Several test cases serve as validation for the approach using tailored Green's functions. They also illustrate the relative benefits of the two propagation operators.

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“…This is consistent with the comparison for three-dimensional calculations reported by Hamiche et al. (2019).…”

Section: Applicationssupporting

confidence: 93%

Section: Free-field Propagationsupporting

confidence: 93%

Section: Propagation In Sheared Non-isothermal Flowsmentioning

confidence: 99%