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Title: Optical monitor for observing turbulent flow

Abstract

The present invention provides an apparatus and method for non-invasively monitoring turbulent fluid flows including anisotropic flows. The present invention uses an optical technique to filter out the rays travelling in a straight line, while transmitting rays with turbulence induced fluctuations in time. The output is two dimensional, and can provide data regarding the spectral intensity distribution, or a view of the turbulence in real time. The optical monitor of the present invention comprises a laser that produces a coherent output beam that is directed through a fluid flow, which phase-modulates the beam. The beam is applied to a temporal filter that filters out the rays in the beam that are straight, while substantially transmitting the fluctuating, turbulence-induced rays. The temporal filter includes a lens and a photorefractive crystal such as BaTiO.sub.3 that is positioned in the converging section of the beam near the focal plane. An imaging system is used to observe the filtered beam. The imaging system may take a photograph, or it may include a real time camera that is connected to a computer. The present invention may be used for many purposes including research and design in aeronautics, hydrodynamics, and combustion.

Inventors:
 [1];  [2]
  1. Livermore, CA
  2. Rochester, NY
Publication Date:
Research Org.:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
OSTI Identifier:
868344
Patent Number(s):
US 5121985
Assignee:
United States of America as represented by United States (Washington, DC)
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
optical; monitor; observing; turbulent; flow; provides; apparatus; method; non-invasively; monitoring; fluid; flows; including; anisotropic; technique; filter; rays; travelling; straight; line; transmitting; turbulence; induced; fluctuations; time; output; dimensional; provide; data; regarding; spectral; intensity; distribution; view; comprises; laser; produces; coherent; beam; directed; phase-modulates; applied; temporal; filters; substantially; fluctuating; turbulence-induced; lens; photorefractive; crystal; batio; positioned; converging; section; near; focal; plane; imaging; observe; filtered; photograph; camera; connected; computer; purposes; design; aeronautics; hydrodynamics; combustion; output beam; fluid flow; focal plane; fluid flows; intensity distribution; turbulent flow; optical technique; optical monitor; straight line; converging section; data regarding; time camera; photorefractive crystal; /356/

Citation Formats

Albrecht, Georg F, and Moore, Thomas R. Optical monitor for observing turbulent flow. United States: N. p., 1992. Web.
Albrecht, Georg F, & Moore, Thomas R. Optical monitor for observing turbulent flow. United States.
Albrecht, Georg F, and Moore, Thomas R. 1992. "Optical monitor for observing turbulent flow". United States. https://www.osti.gov/servlets/purl/868344.
@article{osti_868344,
title = {Optical monitor for observing turbulent flow},
author = {Albrecht, Georg F and Moore, Thomas R},
abstractNote = {The present invention provides an apparatus and method for non-invasively monitoring turbulent fluid flows including anisotropic flows. The present invention uses an optical technique to filter out the rays travelling in a straight line, while transmitting rays with turbulence induced fluctuations in time. The output is two dimensional, and can provide data regarding the spectral intensity distribution, or a view of the turbulence in real time. The optical monitor of the present invention comprises a laser that produces a coherent output beam that is directed through a fluid flow, which phase-modulates the beam. The beam is applied to a temporal filter that filters out the rays in the beam that are straight, while substantially transmitting the fluctuating, turbulence-induced rays. The temporal filter includes a lens and a photorefractive crystal such as BaTiO.sub.3 that is positioned in the converging section of the beam near the focal plane. An imaging system is used to observe the filtered beam. The imaging system may take a photograph, or it may include a real time camera that is connected to a computer. The present invention may be used for many purposes including research and design in aeronautics, hydrodynamics, and combustion.},
doi = {},
url = {https://www.osti.gov/biblio/868344}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Jan 01 00:00:00 EST 1992},
month = {Wed Jan 01 00:00:00 EST 1992}
}

Works referenced in this record:

Photorefractive time differentiation of coherent optical images
journal, January 1987


Optical technique for the measurement of turbulent spectra using the photorefractive properties of BaTiO 3
journal, August 1990


Time-integrating interferometry using photorefractive fanout
journal, January 1988


An optical technique for the direct measurement of the 2-D spectral density of a passive scalar in a turbulent flow
conference, August 1990


Optical novelty filters
journal, March 1989