AN EVALUATION OF THE SMOKE-WIRE TECHNIQUE FOR MEASURING VELOCITIES IN AIR

Abstract

In the smoke-wire technique, oil is evaporated from a very thin, high-resistance wire by the passage of a large electric current through the wire from a capacitor. The resulting line of smoke is carried downstream with the local velocity of the air, deforming so that a photograph of the smoke line after a measured time delay provides a velocity profile. Since the time delay is very short, this velocity profile is very close to the actual velocity profile at the location of the wire. The technique was evaluated in two- and three-dimensional air flows, both laminar and turbulent, by comparisons with theoretical profiles. Experimental velocity profiles compared quite favorably with theoretical solutions for several different types of flows, including boundary layers, jets, wakes, and vortices. Modifications of the technique and associated apparatus were made in order to extend its scope of application.

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Document Details

Document Type
Technical Report
Publication Date
Mar 01, 1967
Accession Number
AD0652275

Entities

People

  • Curren J. Sanders
  • Joe F. Thompson Jr.

Organizations

  • Mississippi State University

Tags

Communities of Interest

  • Weapons Technologies

DTIC Thesaurus Topics

  • Army Aviation
  • Boundaries
  • Boundary Layer
  • Delay Circuits
  • Electric Current
  • Flow
  • Laminar Boundary Layer
  • Layers
  • Leading Edges
  • Military Research
  • Photographs
  • Test And Evaluation
  • Three Dimensional
  • Trailing Edges
  • Turbulent Boundary Layer
  • Turbulent Flow
  • Wind Tunnels

Fields of Study

  • Physics

Readers

  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.
  • Combustion and Flow Dynamics.
  • Electrical Engineering