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Direct numerical simulations of a spatially developing plane wakeIn the present paper, direct numerical methods by which to simulate the spatially developing free shear flows in the transitional region are described and the numerical results of a spatially developing plane wake are presented. The incompressible time-dependent Navier-Stokes equations were solved using Pade finite difference approximations in the streamwise direction, a mapped pseudospectral Fourier method in the cross-stream direction, and a third-order compact Runge-Kutta scheme for time advancement. The unstable modes of the Orr-Sommerfeld equations were used to perturb the inlet of the wake. Statistical analyses were performed and some numerical results were compared with experimental measurements. When only the fundamental mode is forced, the energy spectra show amplification of the fundamental and its higher harmonics. In this case, unperturbed alternate vortices develop in the saturation region of the wake. The phase jitter around the fundamental frequency plays a critical role in generating vortices of random shape and spacing. Large- and small-scale distortions of the fundamental structure are observed. Pairing of vortices of the same sign is observed, as well as vortex coupling of vortices of the opposite sign.
Document ID
19930037295
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Maekawa, Hiroshi
(Univ. of Electro-Communications Chofu, Japan)
Mansour, Nagi N.
(NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
August 16, 2013
Publication Date
November 1, 1992
Publication Information
Publication: JSME International Journal, Series II
Volume: 35
Issue: 4
ISSN: 0914-8817
Subject Category
Fluid Mechanics And Heat Transfer
Accession Number
93A21292
Distribution Limits
Public
Copyright
Other

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