Three-dimensional Effects in Viscous Wakes PDF Download

Author: Martin H. Steiger
Publisher:
ISBN:
Category : Viscosity
Languages : en
Pages : 46

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Book Description
The velocity, energy and concentration fields of three-dimensional viscous wakes are examined with the boundary layer approximations and Oseens' linearization of the acceleration terms. Solutions are derived for both incompressible and compressible wakes, without and with axial pressure gradients. In the incompressible cases the governing equations are linear and transform methods yield exact solutions for general types of initial conditions. In the compressible case the energy equation admits a Crocco integral when the Prandtl and Lewis numbers are equal to unity, and a similar integral of the concentration equation is derived for Le/Pr=1 and Wi tends toward 0. However, due to the nonlinearities associated with compressible flows, solutions for the velocity components can only be achieved by approximate methods. Two methods are presented; the first involves an iteration scheme, while the second assumes that the density and viscosity are only a function of the axial coordinate. In both methods transform theory is used and solutions are presented for general types of initial conditions. As an illustration, it is demonstrated that the axial velocity distribution in isobaric wakes whose initial isovels (lines of constant velocity) are of elliptic shape decay to axial symmetry. (Author).