A Theory and Method for Applying Interferometry to the Measurement of Certain Two-Dimensional Gaseous Density Fields
Abstract
A theory and method are described for the application of interferometry to the measurement of certain two-dimensional gaseous density fields. The theory includes the effects of optical refraction upon the observed interference pattern. Exact equations denoting the relative density difference corresponding to an observed interference-fringe shift and the optical distortion caused by refraction are derived. Corresponding approximations in the form of power series expansions are developed to permit practical application of the theory. Expressions are derived which permit calculation of the values of the power series coefficients from experimental data. The approximations were applied to available interference data in order to determine the density distribution in a boundary layer formed by supersonic air flow along a flat plate. Good agreement was obtained between the density distribution calculated from the interference data and that obtained from pressure-probe measurements. Various methods for verifying the theory are considered and an evaluation process is outlined.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1952
- Accession Number
- ADA380449
Entities
People
- Donald R. Buchele
- Walton L. Howes
Organizations
- National Aeronautics and Space Administration