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Large-Scale Instability of Generalized Oscillating Kolmogorov Flows
The stability of an incompressible unidirectional flow that depends periodically, but otherwise arbitrarily, on a transverse coordinate and on time is considered. An iterative solution of an infinite-dimensional eigenvalue problem is constructed by a rigorous perturbation method. The critical Reynol...
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Published in: | SIAM journal on applied mathematics 1998-04, Vol.58 (2), p.540-564 |
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Main Authors: | , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | The stability of an incompressible unidirectional flow that depends periodically, but otherwise arbitrarily, on a transverse coordinate and on time is considered. An iterative solution of an infinite-dimensional eigenvalue problem is constructed by a rigorous perturbation method. The critical Reynolds number Rc and the critical direction for which the large-scale "eddy viscosity" is minimum (and equal to zero) are determined by a system of two algebraic equations. For both time-independent and time-dependent cases, it turns out that the fastest-growing critical disturbances generally do not have the same transverse periodicity as that of basic flow. In the limit of large frequencies of oscillation, stability is essentially determined by the time-averaged flow. When the latter vanishes, the flow is absolutely stable for sufficiently large frequencies. |
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ISSN: | 0036-1399 1095-712X |
DOI: | 10.1137/s003613999630527x |