DISPERSION OF PARTICLE PAIRS IN HOMOGENEOUS TURBULENCE.

Abstract

The relative dispersion of particle pairs in homogeneous turbulence is treated by the Lagrangian-history direct-interaction closure approximation for a conserved scalar field. Richardson's diffusion equation emerges, with the sole difference that the eddy diffusivity depends on the duration of the dispersion as well as on particle separation. The diffusivity tensor is evaluated in the inertial range, and the probability distribution for the separation distance of a particle pair is computed for long-time, inertial-range dispersion. From this solution, numerical values are obtained for the dimensionless constants in Richardson's law for mean-square separation distance and Oboukhov's scalar-field inertial-range spectrum law. An inequality relating these two constants is inferred from qualitative considerations, without use of the closure approximation. (Author)

Document Details

Document Type
Technical Report
Publication Date
Feb 01, 1966
Accession Number
AD0628541

Entities

People

  • Robert H. Kraichnan

Tags

DTIC Thesaurus Topics

  • Diffusion
  • Diffusivity
  • Dispersions
  • Equations
  • Inequalities
  • Mathematics
  • Particles
  • Probability
  • Probability Distributions
  • Spectra
  • Turbulence

Fields of Study

  • Physics

Readers

  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.
  • Calculus or Mathematical Analysis

Technology Areas

  • AI & ML
  • AI & ML - Bayesian Inference
  • AI & ML - Machine Learning Algorithms