𝔖 Bobbio Scriptorium
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ACOUSTIC–VORTICITY WAVES IN SWIRLING FLOWS

✍ Scribed by V.V. Golubev; H.M. Atassi

Publisher
Elsevier Science
Year
1998
Tongue
English
Weight
299 KB
Volume
209
Category
Article
ISSN
0022-460X

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✦ Synopsis

The propagation of small disturbances in an annular duct with a mean vortical swirling flow is studied. The disturbance velocity is split into a nearly-convected part and a nearly-sonic part, obeying weakly coupled equations. A normal mode analysis shows that the eigenvalues are segregated into a finite number of propagating pressure-dominated nearly-sonic waves and a cluster of infinite number of vorticity-dominated nearly-convected modes. A generalized gust can then be identified with the vorticity-dominated nearly-convected eigensolutions. The nearly-convected eigenvalues form two branches on either side of a critical layer which corresponds to purely convected modes. An asymptotic analysis is used to investigate the stability of the nearly-convected eigensolutions in the vicinity of the critical layer.

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