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Proceedings Paper

Interfermometric tomographic measurement of an instantaneous flow field under adverse environments
Author(s): Enxi Yu; Soyoung Stephen Cha; Alpheus W. Burner
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Paper Abstract

Measurement of an instantaneous flow field by interferometric tomography, that is, reconstruction of a 3D refractive-index field from multidirectional projection data, has ben conducted. In order to simulate the expected experimental arrangement at a wind tunnel, reconstructions are made from a restricted view angle less than 40 degrees and incomplete projections. In addition, appreciable ambient air and experimental setup disturbances are present. A new phase-stepping technique, based on a generalized phase-stepping approach of a four- bucket model, is applied for expeditious and accurate phase information extraction from projection interferograms under the harsh environments. Phase errors caused by the various disturbances, which can include ambient refractive-index change, optical component disturbance, hologram repositioning error, etc., are partially compensated with a linear corrective model. A new computational tomographic technique based on a series expansion approach was also utilized to efficiently deal with arbitrary boundary shapes and the continuous flow fields in reconstruction. The results of the preliminary investigation are encouraging; however, the technique needs to be further developed in the future through refinement of the approaches reported here and through hybridization with previously developed techniques.

Paper Details

Date Published: 29 September 1995
PDF: 12 pages
Proc. SPIE 2546, Optical Techniques in Fluid, Thermal, and Combustion Flow, (29 September 1995); doi: 10.1117/12.221565
Show Author Affiliations
Enxi Yu, Univ. of Illinois/Chicago (United States)
Soyoung Stephen Cha, Univ. of Illinois/Chicago (United States)
Alpheus W. Burner, NASA Langley Research Ctr. (United States)

Published in SPIE Proceedings Vol. 2546:
Optical Techniques in Fluid, Thermal, and Combustion Flow
Soyoung Stephen Cha; James D. Trolinger, Editor(s)

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