Accession Number : ADA184856

Title :   Experimental Study of the Fluid Mechanics of Unsteady Turbulent Boundary Layers.

Descriptive Note : Final rept. 3 Jul 83-6 Jan 86,

Corporate Author : STANFORD UNIV CA THERMOSCIENCES DIV

Personal Author(s) : Brereton, G J ; Reynolds, W C

PDF Url : ADA184856

Report Date : May 1987

Pagination or Media Count : 258

Abstract : An experimental study of the effects of forced, free-stream unsteadiness on turbulent boundary layers was undertaken in an effort to characterize the nature of such flows and to provide guidance for turbulence modelers. A turbulent boundary layer, which had developed under steady, constant-pressure conditions, was locally subjected to a range of frequencies of sinusoidal free-stream unsteadiness. The response of the boundary layer to these free-stream effects was studied through simultaneous measurements of the u and v components of the velocity field, using a two-color laser-doppler anemometer. To focus on the distinct behaviors of the deterministic and time-averaged fields of flow, the equations of fluid motion were reformulated according to a triple decomposition of velocity and pressure into; (i) a time-averaged measure, (ii) a deterministic or organized, unsteady measure, and (iii) a turbulent measure.

Descriptors :   *TURBULENT BOUNDARY LAYER, *UNSTEADY FLOW, FLUID MECHANICS, FREE STREAM, TURBULENCE, LASER VELOCIMETERS, DOPPLER SYSTEMS

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE