Experimental investigation of supersonic/hypersonic flow fields based on a new approach using holographic optical techniques

This paper describes a holographic approach designed to provide a comprehensive acquisition of the optical information obtained from supersonic/hypersonic flow fields. A simultaneous application of three holographic diagnostic techniques, namely, schlieren- and shadowgraphy, moire deflectometry and interferometry, yields a more accurate measurement of the density distribution in complex compressible flow fields. The holographic approach makes it possible to increase the sensitivity of the interferometric measurements with compensation of the optical aberration to suit the low density field of hypersonic flows. Preliminary experiments with the new approach rendered satisfactory results, proving the potential use of these techniques.