Accession Number : AD0615770

Title :   ON THE BIRTH AND DECAY OF VORTICES,

Corporate Author : NAVAL WEAPONS LAB DAHLGREN VA

Personal Author(s) : Lugt,Hans J. ; Schwiderski,Ernst W.

Report Date : APR 1965

Pagination or Media Count : 41

Abstract : Complete sets of time-dependent solutions for Stokes' slow-motion equations are consturcted by means of a generalized separation technique, which was recently introduced and applied by the authors to steady-state flows. Under certain boundary and regularity conditions, such integrals of slow motion can be used to derive solutions of the quasi-linear Navier-Stokes equations in an exact linear manner. The classes of separable solutions, which are presented in the paper, reveal significant mathematical properties of laminar motions concerning their uniqueness and regularity. From the physical point of view, they render valuable information on the mechanism of growing and dying vortices. For instance, it can be shown that a decaying discontinuity line is a process which involves the gradual obliteration of a discrete spectrum of vortices in such a way that little vortices with large damping coefficients dominate first, and that bigger vortices of fewer number replace them with advancing time. This model conforms with photographs by Weske and Rankin. Furthermore, the development and decay of individual vortices together with their energy supply are investigated. (Author)

Descriptors :   (*VORTICES, THEORY), FLUID MECHANICS, ROTATION, CYLINDRICAL BODIES, LAMINAR FLOW, MATHEMATICAL ANALYSIS

Distribution Statement : APPROVED FOR PUBLIC RELEASE