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Oscillatory flow in a stepped channel

Published online by Cambridge University Press:  26 April 2006

O. R. Tutty
Affiliation:
Department of Aeronautics and Astronautics, University of Southampton, Southampton SO9 5NH, UK
T. J. Pedley
Affiliation:
Department of Applied Mathematical Studies, University of Leeds, Leeds LS2 9JT, UK

Abstract

Two-dimensional, unsteady flow of a viscous, incompressible fluid in a stepped channel has been studied by the numerical solution of the Navier–Stokes equation using an accurate finite-difference method.

With a sinusoidal mass flow rate, the problem has three governing parameters: the Reynolds number, the Strouhal number, and the step height. The effects on the flow of varying all three parameters has been investigated systematically. In appropriate parameter regimes, a strong ‘vortex wave’ is generated during the forward phase when the flow is over the step into the expansion. Secondary effects on the wave can result in a complex flow pattern with each major structure of the flow consisting of an eddy with more than one core. No such wave is found during the reverse phase of the flow. The generation and development of the wave is examined in some detail, and our results are compared and contrasted with those of previous studies, both experimental and theoretical, of flow in non-uniform vessels.

Type
Research Article
Copyright
© 1993 Cambridge University Press

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