Quantitative Flow Visualization of Correctly Expanded Supersonic Jets by Rainbow Schlieren Deflectometry

Abstract

A quantitative visual study of a correctly-expanded supersonic jet of a Mach number of 1.6 by the rainbow schlieren deflectometry has been conducted to reveal the jet flow field quantitatively. Rainbow schlieren images of the jet have been taken by a schlieren system with a rainbow filter which has a continuous hue distribution. The density contour plot of the jet flow is determined by using the image analysis based on the Abel inversion of experimental data of transverse displacement at the cutoff plane. Also, Pitot probe measurements at a jet cross-section have been carried out to obtain density profiles. The radial distribution of the density from the schlieren quantitatively agrees well with that from the Pitot probe.

Strut Fuel Injector Penetration and Mixing Enhancement for a Dual-mode Scramjet

“…This phenomena was shown for a simple jet in supersonic co-flow using rainbow schlieren. [4,80] If air is added to the jet such that its mole fraction is still uniform, but still not mixing with the surrounding air flow, then the overall magnitude of the signal would decrease, but the shape of the distribution would still be the same. This means that the BOS signal is dependent on both the magnitude of the change in density across the Line-Of-Sight (LOS), i.e., magnitude of helium mole fraction, and also the line width of the disturbance that the light ray travels through, i.e., the cross-sectional shape of the disturbance.…”