Görtler vortices in the Rayleigh layer on an impulsively started cylinder
journal contributionposted on 2023-05-18, 17:50 authored by MacKerrell, SO, Andrew BassomAndrew Bassom
Centripetal instabilities in two flows involving time-dependent Rayleigh layers on a rotating circular cylinder are examined. In one case we consider the stability of the flow induced in an infinite expanse of quiescent fluid when the cylinder is impulsively given a constant angular velocity; in the other problem the angular velocity increases as the square root of time so that the undisturbed flow has a constant wall shear. For both situations linear neutral stability curves for vortex motions are calculated by quasi-steady (or frozen-time) methods, with these results justified, where possible, by Wentzel-Kramers-Brillouin techniques. The topology of the neutral curve for the ramped angular velocity configuration allows a rigorous description of small wavelength, weakly and fully nonlinear vortex structures to be obtained. Our results are compared with the equivalent cases that arise in the study of unsteady thermal Rayleigh layers induced by the sudden heating of a horizontal flat plate.
Publication titlePhysics of Fluids
Department/SchoolSchool of Natural Sciences
PublisherAmer Inst Physics
Place of publicationCirculation & Fulfillment Div, 2 Huntington Quadrangle, Ste 1 N O 1, Melville, USA, Ny, 11747-4501
Rights statementCopyright 2002 American Institute of Physics