The parabolised stability equations for 3D-flows: implementation and numerical stability
The numerical implementation of the parabolised stability equations (PSE) using a spectral/ hp-element discretisation is considered, and the numerical stability of the governing equations is presented. Analogous to the primitive variable form of the two-dimensional PSE, the equations are ill-posed;...
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Published in: | Applied numerical mathematics Vol. 58; no. 7; pp. 1017 - 1029 |
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Main Authors: | , |
Format: | Journal Article Conference Proceeding |
Language: | English |
Published: |
Amsterdam
Elsevier B.V
01-07-2008
Elsevier |
Subjects: | |
Online Access: | Get full text |
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Summary: | The numerical implementation of the parabolised stability equations (PSE) using a spectral/
hp-element discretisation is considered, and the numerical stability of the governing equations is presented. Analogous to the primitive variable form of the two-dimensional PSE, the equations are ill-posed; although choosing an Euler implicit scheme in the streamwise
z-direction yields a stable scheme for sufficiently large step sizes (
Δ
z
>
1
/
|
β
|
, where
β is the streamwise wavenumber). The source of the instability is a residual ellipticity that remains in the equations, and presents itself as an upstream propagating acoustic wave. Neglecting this term relaxes the lower limit on the step-size restriction. The
θ-scheme is also considered, allowing the step-size restriction of the scheme to be determined. The explicit scheme is always unstable, whereas neglecting the pressure gradient term shows stable eigenspectra for
θ
⩾
0.5
. |
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ISSN: | 0168-9274 1873-5460 |
DOI: | 10.1016/j.apnum.2007.04.016 |