Optical Measurement of a Compressible Shear Layer Using a Laser-Induced Air Breakdown Beacon (Preprint)

Abstract

The aero-optic aberrations due to a compressible shear-layer flow high-and low- speed Mach numbers of 0.75 and 0.12 were measured using the return light from an artificial guide star. The guide star was created by focusing a pulsed, frequency-tripled Nd:YAG laser emitting in the ultraviolet to create a laser-induced air breakdown spark. The experiments showed that accurate wavefront data could be obtained, including accurate measurements of the wavefront tip/tilt, when the shear layer was forced and the measurements were phase-locked to the forcing signal. Issues involved in integrating the beacon system into a feed forward adaptive-optic correction approach are discussed.

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Document Details

Document Type
Technical Report
Publication Date
Dec 01, 2009
Accession Number
ADA520394

Entities

People

  • David Cavalieri
  • David Goorskey
  • Eric J. Jumper
  • Garnett Cross
  • Matthew R. Whiteley
  • R. M. Rennie

Tags

Communities of Interest

  • Air Platforms
  • Materials and Manufacturing Processes
  • Sensors
  • Space

DTIC Thesaurus Topics

  • Aeronautics
  • Air Force
  • Air Force Research Laboratories
  • Astronautics
  • Diameters
  • Engineering
  • Frequency
  • Geometry
  • Laser Beams
  • Lasers
  • Mach Number
  • Measurement
  • Mechanical Engineering
  • Turbulent Mixing
  • Wavefronts
  • Wind Tunnels
  • Yag Lasers

Fields of Study

  • Physics

Readers

  • Aerospace Test and Evaluation
  • Fluid Mechanics and Fluid Dynamics.
  • Optical Physics and Photonics.

Technology Areas

  • Directed Energy