Experimental Studies of Unsteady Phenomena in Boundary Layers,

Abstract

The stability of decelerating boundary layer flow is investigated experimentally and numerically. Experimentally, a flat plate having a Blasius boundary layer is decelerated in an 18-m towing tank. The boundary layer becomes unstable to two-dimensional waves which break down into three-dimensional patterns, hairpin vortices, and finally turbulent bursts when the vortices lift off the wall. The unsteady boundary layer equations are solved numerically to generate instantaneous velocity profiles for a range of boundary and initial conditions. A quasi-steady approximation is invoked and the stability of local velocity profiles are determined by solving the Orr-Sommerfeld equation using Chebyshev matrix methods. Comparisons are made between the numerical predictions and the experimentally observed instabilities. (Author)

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Document Details

Document Type
Technical Report
Publication Date
May 01, 1983
Accession Number
ADA133769

Entities

People

  • Mohamed Gad-el-hak

Tags

Communities of Interest

  • Materials and Manufacturing Processes

DTIC Thesaurus Topics

  • Air Force
  • Boundary Layer
  • Boundary Layer Flow
  • Chebyshev Polynomials
  • Computational Fluid Dynamics
  • Computational Science
  • Differential Equations
  • Equations
  • Flow Fields
  • Flow Visualization
  • Fluid Dynamics
  • Fluid Mechanics
  • Hydrodynamics
  • Lasers
  • Reynolds Number
  • Stratified Fluids
  • Two Dimensional

Fields of Study

  • Physics

Readers

  • Finite Element Method (FEM) for solving Partial Differential Equations (PDEs)
  • Fluid Dynamics.
  • Fluid Mechanics and Fluid Dynamics.