Boundary layers on stationary and rotating disks have received much attention since von Kaacute;rmaacute;nrsquo;s lsqb;Z. Angew. Math. Mech.1, 233 (1921)rsqb; and Bouml;dewadtrsquo;s lsqb;Z. Angew. Math. Mech.20, 241 (1940)rsqb; studies of the cases with disks of infinite radius. Theoretical treatments have focused on similarity treatments leading to conflicting ideas about existence and uniqueness, and where selfhyphen;similar solutions exist, whether they are physically realizable. The coupling between the boundary layer flows and the interior flow between them, while being of practical importance in a variety of situations such as turbomachinery and ocean circulations, is not well understood. Here, a numerical treatment of the axisymmetric Navierndash;Stokes equations, together with some experiments for the case of finite stationary and rotating disks bounded by a cohyphen;rotating sidewall is presented. We show that in the long time limit, solutions are steady and essentially selfhyphen;similar. Yet the transients are not. In particular, axisymmetric waves propagate in the stationary disk boundary layer when the vortex lines entering the boundary layer develop inflection points, and there are subsequent eruptions of vortical flow out of the boundary layer deep into the interior at large Reynolds numbers. copy;1996 American Institute of Physics.
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