Three-Dimensional Structure of Boundary Layers in Transition to Turbulence

Abstract

The Floquet theory of secondary instability in shear flows has been further developed and applied to a variety of flows. The linear theory has been extended to explain and quantitatively analyze the observed combination resonance in boundary layers. Numerical methods for the study of secondary instability in unbounded flows have been developed and applied to the viscous and inviscid mixing layer. The linear theory has been formulated for a variety of spatially periodic flows that include Gortler vortices and oblique waves. Applications await accounting for nonparallel effects. A new approach to analyzing nonparallel flows based on parabolic partial differential equations has been successfully applied to the primary stability problem. A perturbation method has been successfully applied to the primary stability problem. A perturbation method has been developed to reveal the nonlinear interactions that lead to breakdown of the laminar flow. This method permits prediction of the transition location in a given disturbance environment. Keywords: Boundary layer transitions; Instability, Gortler vortices.

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Document Details

Document Type
Technical Report
Publication Date
Feb 06, 1989
Accession Number
ADA205587

Entities

People

  • Herbert Thornwald

Organizations

  • Virginia Tech

Tags

Communities of Interest

  • Air Platforms
  • Human Systems
  • Space

DTIC Thesaurus Topics

  • Boundaries
  • Boundary Layer
  • Boundary Layer Transition
  • Computational Fluid Dynamics
  • Contracts
  • Differential Equations
  • Equations
  • Flow
  • Fluid Dynamics
  • Fluid Mechanics
  • Laminar Flow
  • Layers
  • Partial Differential Equations
  • Shear Flow
  • Three Dimensional
  • Turbulence
  • Universities

Fields of Study

  • Physics

Readers

  • Control Systems Engineering.
  • Fluid Mechanics and Fluid Dynamics.