Accession Number : ADA206980

Title :   Reciprocal Interactions of Hairpin-Shaped Vortices and a Boundary Layer.

Descriptive Note : Final rept. 1 Feb 86-31 Dec 88,

Corporate Author : SCIENTIFIC RESEARCH ASSOCIATES INC GLASTONBURY CT

Personal Author(s) : Liu, N S ; Shamroth, S J ; McDonald, H

PDF Url : ADA206980

Report Date : 31 Dec 1988

Pagination or Media Count : 296

Abstract : The role of hairpin vortices in cyclic production of wall turbulence has been studied in many laboratory experiments, primarily by using flow visualization. Study of hairpin vortices in a fully turbulent environment is greatly complicated by the presence of jitters and other co-existing structures. A viable approach for obtaining better understanding of the role of hairpin vortices in turbulence dynamics is to study the flow events stimulated by synthetically generated hairpin vortices in initially laminar boundary layers. This study simulates the flow dynamics stimulated by hairpin-shaped vortices in a boundary layer through the solution of time-dependent, three-dimensional, compressible Navier-Stokes equations. The numerical scheme used leads to temperal-spatial simulations and could be easily applied to future simulations focusing upon the effects of pressure gradient and compressibility on turbulence structure. Two simulations were carried out. In the first case, the initial condition contains only one imposed hairpin-shaped vortex; in the second, there are two incipient vortices separated by a short distance in the streamwise direction. Organized flow events; Three dimensional flow. (jes)

Descriptors :   *BOUNDARY LAYER, COMPRESSIBLE FLOW, COMPRESSIVE PROPERTIES, CYCLES, DYNAMICS, ENVIRONMENTS, FLOW, FLOW VISUALIZATION, FOCUSING, INTERACTIONS, LABORATORY TESTS, LAMINAR BOUNDARY LAYER, NAVIER STOKES EQUATIONS, NUMERICAL ANALYSIS, PRESSURE GRADIENTS, PRODUCTION, SHORT RANGE(DISTANCE), SIMULATION, SOLUTIONS(GENERAL), THREE DIMENSIONAL FLOW, TIME DEPENDENCE, TURBULENCE, VORTICES, WALLS

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE