CALCULATION OF THE DIFFUSION OF SMALL PARTICLES IN A NON-UNIFORM ATMOSPHERE

Abstract

The downward motion of small particles in an isothermal turbulence free atmosphere was studied for the case of variable diffusion coefficient, utilizing two models. In the first of these, the diffusion coefficient was taken as an exponential function of altitude while in the second, the variation was assumed to be parabolic. In the exponential model an analytic solution for simultaneous diffusion in the vertical and horizontal directions was obtained; while for the parabolic model, an analytic solution for vertical motion only was obtained. The calculations, which were restricted to the exponential case show the development of a profile of constant shape, all points of which move with the same velocity, independent of the mass of the particles. These results are in agreement with the numerical work of Banister and Davis. It is also shown that the qualitative nature of the results is independent of the initial distribution. (Author)

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Jun 01, 1962
Accession Number
AD0285252

Entities

People

  • Kwang Yu
  • Milton M. Klein

Tags

Communities of Interest

  • Air Platforms
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Altitude
  • Atmospheres
  • Bessel Functions
  • Boundaries
  • Coefficients
  • Collisions
  • Delta Functions
  • Differential Equations
  • Diffusion
  • Diffusion Coefficient
  • Equations
  • Exponential Functions
  • Government Procurement
  • Gravitational Fields
  • Integrals
  • Step Functions
  • Three Dimensional

Readers

  • Calculus or Mathematical Analysis
  • Fluid Dynamics.
  • Oceanography.