On Separating Turbulent Boundary Layers,
Abstract
Some data and theories of two dimensional turbulent boundary layer separation are considered. A description of separating layers based on the Schofield and Perry similarity is proposed. It is shown that the Schofield and Perry defect law can describe detached profiles as accurately as it can describe attached profiles if the origin is shifted, from the wall, out to the zero velocity position in the detached flow. For attached flow the inner wall matching condition is the usual law of the wall. For detached flow the wall matching condition is provided by the reversed flow for which a modified similarity scale is proposed. This extended validity of the Schofield and Perry defect law implies a unique progression of mean velocity profile shapes up to and through separation. Good experimental support for this theoretical results is presented. Experimental evidence also supports the proposition that detachment (and perhaps reattachment) always occurs at the same position on the locus of profile shapes, that is, boundary layers detach with a universal mean profile shape. A comparison of this result with other separation theories leads to another conclusion: that layers which separate in moving equilibrium not only detach with the same mean profile shape, but detach at the same local pressure gradient. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1983
- Accession Number
- ADA143190
Entities
People
- W. H. Schofield