TERMINAL VELOCITIES OF WINDOW DIPOLES USED IN HIGH ALTITUDE WIND MEASUREMENTS

Abstract

Various theoretical formulae for the rate-offall of window dipoles at altitudes up to 100 Km are shown to be in close agreement with the best available experimental data. At low altitudes velocity is determined mainly by conventional aerodynamic drag. At approximately 20 Km, Lamb's theory of viscous flow is required whilst at 50-70 Km, corrections must be applied for 'slip- flow'. Finally, above about 75 Km, 'free molecule flow' theory is needed to get good agreement with experiment. For the most accurate measurements of wind structure it is desirable to employ dipoles with the smallest possible terminal velocity. This means that the dipoles should have low density and the smallest possible thickness.

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Document Details

Document Type
Technical Report
Publication Date
Nov 01, 1964
Accession Number
AD0457278

Entities

People

  • T. W. Dawson

Organizations

  • Royal Aircraft Establishment

Tags

Communities of Interest

  • Air Platforms
  • Weapons Technologies

DTIC Thesaurus Topics

  • Aerodynamic Drag
  • Altitude
  • Boundary Layer
  • Drag
  • Experimental Data
  • Flow
  • Ground Level
  • High Altitude
  • Hydrodynamics
  • Low Altitude
  • Mach Number
  • Mean Free Path
  • Measurement
  • Reynolds Number
  • Skin Friction
  • Slip Flow
  • Viscous Flow

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