Singular Perturbation and Turbulent Shear Flow near Walls.
PURDUE UNIV LAFAYETTE IND PROJECT SQUID HEADQUARTERS
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The method of matched asymptotic expansions is applied to fully turbulent shear flow near walls in the limit of an appropriately defined Reynolds number tending to infinity. In particular, turbulent pipechannel flow and boundary-layer flow on a flat plate with an external pressure gradient upstream of any separation is examined. The relevant Reynolds number is the ratio of the turbulent stress to the Newtonian stress. For the postulated expansions, the logarithmic profile, wall friction law, and classical similarity results are deduced without an explicit closure condition relating theturbulent stress to the Newtonian stress. Continuation to higher order is shown to be in general indeterminate without additional physical input to the formulation. Author
- Fluid Mechanics