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Solving Galbrun’s Equation with a Discontinuous galerkin Finite Element Method

Maeder, Marcus ; Peplow, Andrew LU orcid ; Meindl, Maximilian and Marburg, Steffen (2019) In Acta Acustica united with Acustica 105(6). p.1149-1163
Abstract

Over many years, scientists and engineers have developed a broad variety of mathematical formulations to investigate the propagation and interactions with flow of flow-induced noise in early-stage of product design and development. Beside established theories such as the linearized Euler equations (LEE), the linearized Navier–Stokes equations (LNSE) and the acoustic perturbation equations (APE) which are described in an Eulerian framework, Galbrun utilized a mixed Lagrange–Eulerian framework to reduce the number of unknowns by representing perturbations by means of particle displacement only. Despite the advantages of fewer degrees of freedom and the reduced effort to solve the system equations, a computational approach using standard... (More)

Over many years, scientists and engineers have developed a broad variety of mathematical formulations to investigate the propagation and interactions with flow of flow-induced noise in early-stage of product design and development. Beside established theories such as the linearized Euler equations (LEE), the linearized Navier–Stokes equations (LNSE) and the acoustic perturbation equations (APE) which are described in an Eulerian framework, Galbrun utilized a mixed Lagrange–Eulerian framework to reduce the number of unknowns by representing perturbations by means of particle displacement only. Despite the advantages of fewer degrees of freedom and the reduced effort to solve the system equations, a computational approach using standard continuous finite element methods (FEM) suffers from instabilities called spurious modes that pollute the solution. In this work, the authors employ a discontinuous Galerkin approach to overcome the difficulties related to spurious modes while solving Galbrun’s equation in a mixed and pure displacement based formulation. The results achieved with the proposed approach are compared with results from previous attempts to solve Galbrun’s equation. The numerical determination of acoustic modes and the identification of vortical modes is discussed. Furthermore, case studies for a lined-duct and an annulus supporting a rotating shear-flow are investigated.

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author
; ; and
publishing date
type
Contribution to journal
publication status
published
subject
in
Acta Acustica united with Acustica
volume
105
issue
6
pages
15 pages
publisher
EDP Sciences
external identifiers
  • scopus:85077953005
ISSN
1610-1928
DOI
10.3813/aaa.919369
language
English
LU publication?
no
id
39478b36-c5be-4065-a313-103a5883f640
date added to LUP
2021-01-20 18:26:23
date last changed
2022-04-26 23:50:48
@article{39478b36-c5be-4065-a313-103a5883f640,
  abstract     = {{<p>Over many years, scientists and engineers have developed a broad variety of mathematical formulations to investigate the propagation and interactions with flow of flow-induced noise in early-stage of product design and development. Beside established theories such as the linearized Euler equations (LEE), the linearized Navier–Stokes equations (LNSE) and the acoustic perturbation equations (APE) which are described in an Eulerian framework, Galbrun utilized a mixed Lagrange–Eulerian framework to reduce the number of unknowns by representing perturbations by means of particle displacement only. Despite the advantages of fewer degrees of freedom and the reduced effort to solve the system equations, a computational approach using standard continuous finite element methods (FEM) suffers from instabilities called spurious modes that pollute the solution. In this work, the authors employ a discontinuous Galerkin approach to overcome the difficulties related to spurious modes while solving Galbrun’s equation in a mixed and pure displacement based formulation. The results achieved with the proposed approach are compared with results from previous attempts to solve Galbrun’s equation. The numerical determination of acoustic modes and the identification of vortical modes is discussed. Furthermore, case studies for a lined-duct and an annulus supporting a rotating shear-flow are investigated.</p>}},
  author       = {{Maeder, Marcus and Peplow, Andrew and Meindl, Maximilian and Marburg, Steffen}},
  issn         = {{1610-1928}},
  language     = {{eng}},
  number       = {{6}},
  pages        = {{1149--1163}},
  publisher    = {{EDP Sciences}},
  series       = {{Acta Acustica united with Acustica}},
  title        = {{Solving Galbrun’s Equation with a Discontinuous galerkin Finite Element Method}},
  url          = {{http://dx.doi.org/10.3813/aaa.919369}},
  doi          = {{10.3813/aaa.919369}},
  volume       = {{105}},
  year         = {{2019}},
}