ANALYTICAL THEORIES OF TURBULENCE,

Abstract

The paper surveys the current state of analytical attempts at a theory of turbulence. The formulation of the problem in terms of moments is discussed. The difficulty posed by the closure problem is examined in detail using the quasi-normal approximation as an example. The notion of dynamical relaxation by nonlinear scrambling leads to the introduction of eddy relaxation times and the direct-interaction approximation. The properties of the direct-interaction approximation are indicated. Finally, a comparison is made between numerical solution of the equations of turbulence theory and direct numerical simulation of the Navier-Stokes equations. (Author)

Document Details

Document Type
Technical Report
Publication Date
Aug 01, 1969
Accession Number
AD0693194

Entities

People

  • Steven A. Orszag

Organizations

  • Boeing

Tags

DTIC Thesaurus Topics

  • Differential Equations
  • Equations
  • Equations Of Motion
  • Mathematics
  • Navier Stokes Equations
  • Partial Differential Equations
  • Relaxation Time
  • Simulations
  • Turbulence

Readers

  • Calculus or Mathematical Analysis
  • Fluid Dynamics.