Accession Number : ADA132906

Title :   Nonuniqueness in Wakes and Boundary Layers,


Personal Author(s) : Smith,F T

PDF Url : ADA132906

Report Date : May 1983

Pagination or Media Count : 52

Abstract : In streamlined flow past a flat plate aligned with a uniform stream, it is shown that (a) the Goldstein near-wake and (b) the Blasius boundary layer are nonunique solutions locally for the classical boundary layer equations, whereas (c) the Rott-Hakkinen very-near-wake appears to be unique. In each of (a), (b) an alternative solution exists which has reversed flow and which apparently cannot be discounted on immediate grounds. Thus, depending mainly on how the alternatives for (a), (b) develop downstream, the symmetric flow at high Reynolds numbers could have 2, 4 or more, simple steady forms. Concerning non-streamlined flow, e.g. past a bluff obstacle, new similarity forms are described for the pressure-free viscous symmetric closure of a predominantly slender long wake beyond a large-scale separation. Features arising include nonuniqueness, singularities and algebraic behavior, consistent with nonentraining shear layers with algebraic decay. Nonuniqueness also seems possible in reattachment onto a solid surface and for nonsymmetric or pressure-controlled flows including the wake of a symmetric cascade.

Descriptors :   *Boundary layer flow, *Wake, Flat plate models, Equations of motion, Partial differential equations, Reynolds number, Downstream flow

Subject Categories : Numerical Mathematics
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE