Modelling the Transitional Boundary Layer

Abstract

Recent developments in the modelling of the transition zone in the boundary layer are reviewed (the zone being defined as extending from the station where intermittency begins to depart from zero to that where it is nearly unity). The value of using a new non-dimensional spot formation rate parameter, and the importance of allowing for so-called subtransitions within the transition zone, are both stressed. Models do reasonably well in constant pressure 2-dimensional flows, but in the presence of strong pressure gradients further improvements are needed. The linear combination approach works surprisingly well in most cases, but would not be so successful in situations where a purely laminar boundary layer would separate but a transitionalone would not. Intermittency-weighted eddy viscosity methods do not predict peak surface parameters well without the introduction of an overshooting transition function whose connection with the spot theory of transition is obscure. Suggestions are made for further work that now appears necessary for developing improved models of the transition zone.

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Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1990
Accession Number
ADA232080

Entities

People

  • R. Narasimha

Tags

Communities of Interest

  • Energy and Power Technologies
  • Materials and Manufacturing Processes

DTIC Thesaurus Topics

  • Boundaries
  • Boundary Layer
  • Computational Fluid Dynamics
  • Engineering
  • Equations
  • Experimental Data
  • Fluid Dynamics
  • Geometry
  • Heat Transfer
  • Laminar Boundary Layer
  • Layers
  • Pressure Gradients
  • Rate Of Formation
  • Three Dimensional
  • Turbulent Flow
  • Turbulent Mixing
  • Two Dimensional

Readers

  • Fluid Mechanics and Fluid Dynamics.
  • Marine Ecological Systems Migration
  • Theoretical Analysis.