Figure 1: The initial perturbation to v_{y} ( left panel), the shear layer ( middle panel), and the pressure evolution throughout the computation at the upper boundary ( right panel). | |
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Figure 2: The evolution of the mean vertical component of the velocity. The upper panel depicts an absolute instability while a convectiveinstability can be observed on the lower panel. | |
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Figure 3: Response of an incompressible flow to an initial perturbation at various snapshots. Streamlines are plotted for two physically distinct behaviours: a) convectively unstable U_{0}=0.4 ( top row), b) and absolutely unstable U_{0}=0.0 ( bottom row). | |
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Figure 4: Response of an incompressible flow to an initial perturbation. The vertical component of velocity (v_{y}) is plotted for two physically distinct behaviours: convectively unstable U_{0}=0.4 ( left) and absolutely unstable U_{0}=0.0 ( right). | |
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Figure 5: Variation of the growth rates with U_{0} for an incompressible fluid. The dot-dashed line represents the threshold found by Huerre & Monkewitz (1985). Note the excellent agreement found between the numerical and analytical approach. | |
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Figure 6: Variation of the growth rates with U_{0} for a compressible fluid (dashed line) and for an incompressible fluid (solid line). | |
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Figure 7: Variation of the critical mean flow () with the Sonic Mach number () for an inviscid fluid. The asterisks mark the values found in the numerical simulations. | |
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Figure 8: Response of a compressible flow at various snapshots. Streamlines for two different behaviours: a) convectively unstable, e.g. U_{0}=0.4, ( top row) and b) absolutely unstable, e.g. U_{0}=0.0 ( bottom row). | |
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Figure 9: Response of a compressible flow to an initial perturbation. The vertical component of velocity v_{y} for a convectively unstable (U_{0}=0.4, left) and absolutely unstable (U_{0}=0.0, right) shear flow. | |
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Figure 10: Response of a viscous flow at various snapshots with a Reynolds number Re=1000. Streamlines are plotted for a) convectively unstable (e.g. U_{0}=0.4, top row) and b) absolutely unstable (e.g. U_{0}=0.0 bottom row) shear flows, respectively. | |
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Figure 11: Response of a viscous flow with a Reynolds number Re=1000 where the vertical component v_{y} of the velocity is plotted for a) convectively unstable (e.g. U_{0}=0.4, left) and b) absolutely unstable (e.g. U_{0}=0.0, right) shear flows. | |
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Figure 12: Variation of the growth rates as a function of the mean flow U_{0} for a viscous compressible fluid with Reynolds number Re=10^{3} (dashed line) and for an inviscid incompressible fluid (solid line). | |
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Figure 13: Variation of the critical mean flow () with the Reynolds number (Re) for Mach number 0.83 (compressible case). The dotted line shows the value found in the inviscid case (). The asterisks mark the values found in the numerical simulations. | |
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