A Fourier Pseudospectral Method for Some Computational Aeroacoustics Problems

Huang, Xun; Zhang, Xin

doi:10.1260/1475-472x.5.3.279

Cited by 18 publications

(9 citation statements)

References 15 publications

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“…Finally, for R n = 0.9 and R n = 1, the absolute error is homogeneous with errors of the order of −15 dB; however, the limitation to obtain completely reflective surfaces is not new, since it has been also reported in other publications such as Ref. [42].…”

Section: Resultsmentioning

confidence: 72%

Impedance boundary conditions for pseudo-spectral time-domain methods in room acoustics

2010

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The Pseudo-Spectral Time Domain (PSTD) method is an alternative time-marching method to classical leapfrog finite difference schemes in the simulation of wave-like propagating phenomena. It is based on the fundamentals of the Fourier transform to compute the spatial derivatives of hyperbolic differential equations. Therefore, it results in an isotropic operator that can be implemented in an efficient way for room acoustics simulations. However, one of the first issues to be solved consists on modeling wall absorption. Unfortunately, there are no references in the technical literature concerning to that problem. In this paper, assuming real and constant locally reacting impedances, several proposals to overcome this problem are presented, validated and compared to analytical solutions in different scenarios.

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Section: Resultsmentioning

confidence: 72%

Impedance boundary conditions for pseudo-spectral time-domain methods in room acoustics

2010

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“…A higher-order scheme may be more preferable for acoustic modeling in terms of accuracy. 20 On the other hand, the hard-wall boundary condition ðv 0 ¼ 0Þ is implicitly enforced in Eq. (23).…”

Section: Numerical Tests and Discussionmentioning

confidence: 99%

Acoustic imaging of a duct spinning mode by the use of an in-duct circular microphone array

Wei

Huang

Peers

2013

The Journal of the Acoustical Society of America

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An imaging method of acoustic spinning modes propagating within a circular duct simply with surface pressure information is introduced in this paper. The proposed method is developed in a theoretical way and is demonstrated by a numerical simulation case. Nowadays, the measurements within a duct have to be conducted using in-duct microphone array, which is unable to provide information of complete acoustic solutions across the test section. The proposed method can estimate immeasurable information by forming a so-called observer. The fundamental idea behind the testing method was originally developed in control theory for ordinary differential equations. Spinning mode propagation, however, is formulated in partial differential equations. A finite difference technique is used to reduce the associated partial differential equations to a classical form in control. The observer method can thereafter be applied straightforwardly. The algorithm is recursive and, thus, could be operated in real-time. A numerical simulation for a straight circular duct is conducted. The acoustic solutions on the test section can be reconstructed with good agreement to analytical solutions. The results suggest the potential and applications of the proposed method.

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“…This appendix introduces a Fourier based pseudospectral time-domain (PSTD) method that is applied to wave propagation problems pertinent to CAA [160]. This chapter has little connection with the previously presented AMR work.…”

Section: Methodsmentioning

confidence: 99%

Adaptive Mesh Refinement for Computational Aeroacoustics

Huang

Zhang

2005

11th AIAA/CEAS Aeroacoustics Conference

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This thesis describes a parallel block-structured adaptive mesh refinement (AMR) method that is employed to solve some computational aeroacoustic problems with the aim of improving the computational efficiency. AMR adaptively refines and coarsens a computational mesh along with sound propagation to increase grid resolution only in the area of interest.While sharing many of the same features, there is a marked difference between the current and the established AMR approaches. Rather than low-order schemes generally used in the previous approaches, a high-order spatial difference scheme is employed to improve numerical dispersion and dissipation qualities. To use a highorder scheme with AMR, a number of numerical issues associated with fine-coarse block interfaces on an adaptively refined mesh, such as interpolations, filter and artificial selective damping techniques and accuracy are addressed. In addition, the asymptotic stability and the transient behaviour of a high-order spatial scheme on an adaptively refined mesh are also studied with eigenvalue analysis and pseudospectra analysis respectively. In addition, the fundamental AMR algorithm is simplified in order to make the work of implementation more manageable.Particular emphasis has been placed on solving sound radiation from generic aero-engine bypass geometry with mean flow. The approach of AMR is extended to support a body-fitted multi-block mesh. The radiation from an intake duct is modelled by the linearised Euler equations, while the radiation from an exhaust duct is modelled by the extended acoustic perturbation equations to suppress hydrodynamic instabilities generated in a sheared mean flow. After solving the near-field sound solution, the associated far-field sound directivity is estimated by solving the Ffowcs Williams-Hawkings equation. The overall results demonstrate the accuracy and the efficiency of the presented AMR method, but also reveal some limitations. The possible methods to avoid these limitations are given at the end of this thesis.

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A Fourier Pseudospectral Method for Some Computational Aeroacoustics Problems

Cited by 18 publications

References 15 publications

Impedance boundary conditions for pseudo-spectral time-domain methods in room acoustics

Impedance boundary conditions for pseudo-spectral time-domain methods in room acoustics

Acoustic imaging of a duct spinning mode by the use of an in-duct circular microphone array

Adaptive Mesh Refinement for Computational Aeroacoustics

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