Study of Unsteady Turbulent Boundary Layers.
Abstract
A turbulent boundary layer, subjected to a free-stream velocity which changes sinusiodally in time under a zero time mean pressure gradient, is studied both experimentally and analytically. Using a two-component Laser Doppler Anemometer and a Heat Flux Gage, detailed and high quality information is obtained on the instantaneous velocity distribution and wall shear stress, respectively, at various stations. An asymptotic theory, for large Reynolds numbers, is developed for the oscillatory motion. It is valid for both boundary layers at arbitrary time-mean pressure gradients and fully developed pipe and channel flow, and is successfully applied to the present and previous available experimental information. The theory identifies two frequency parameters, in terms of which four different frequency regimes are defined. Similarity laws are identified for each one of these frequency regimes. All the experimental data have been archived on magnetic tape. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 31, 1983
- Accession Number
- ADA138156
Entities
People
- A. N. Menendez
- B. R. Ramaprian
Organizations
- University of Iowa