Sommario
In questo lavoro si studia nel moto piano di Poiseuille il comportamento ed il segno dello stress di Reynolds per perturbazioni periodiche di ampiezza finita. E' trattato il caso del numero di Reynolds 250 e del numero d'onda λ=1. Si osserva che lo stress di Reynolds, che nel caso lineare era di segno opposto alla viscosità, diventa tale per ampiezza della perturbazione rilevante rispetto alla dinamica del moto medio. Sono dati alcuni risultati numerici che caratterizzano il fenomeno.
Summary
The behaviour and sign of the Reynolds stress for periodic perturbation of finite amplitude is studied in this paper for the plane Poiseuille flow. The case considered has Reynolds number 250 and wave number λ=1. The Reynolds stress that in the linear case was of opposite sign with respect to the viscosity, in the case considered becomes such for perturbation amplitudes which are still significant with respect to the dynamics of the mean flow. Some numerical results are given to characterize the phenomenon.
References
E. Bellomo,A numerical program for dealing with finite amplitude disturbances in plane parallel laminar flows, Meccanica, no. 2, p. 95, 1967.
E. Bellomo,Transverse disturbances in plane Poiseuille flow. Two examples as a check of a numerical program for finite-amplitude disturbances in parallel flows, Meccanica, no. 4, p. 109, 1969.
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This work is part of a research program on hydrodynamics at the Istituto di Elaborazione dell'Informazione of the C.N.R., Pisa. The first Author has suggested and precisely formulated the problem, whereas the numerical work was carried out by the second Author.
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Bellomo, E., Cecchi, M.M. Non linear transverse disturbances in plane poiseuille flow at low Reynolds numbers — Part I. Meccanica 5, 270–276 (1970). https://doi.org/10.1007/BF02145651
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DOI: https://doi.org/10.1007/BF02145651