Measurements in correctly expanded supersonic jets by rainbow schlieren deflectometry

Rainbow schlieren deflectometry technique with a filter of a continuous spectrum of colors provides a simple way to obtain the entire density field of an axisymmetric flow field. This technique is capable of providing useful qualitative and quantitative information on the spatial variations in the fluid density without the introduction of additives into the fluid. Experiments on rainbow schlieren deflectometry have been conducted using a supersonic jet issuing from an axisymmetric nozzle of design Mach number 1.6. The ratio of plenum to back pressures is kept constant at 4.25 of its shockfree condition. A density distribution on a jet cross-section is obtained by using the Abel inversion of experimental data of light ray transverse displacement at the filter plane. Also, Pitot pressures at the cross-section have been measured to obtain density profile. For the density profile obtained, good quantitative agreement is reached between measurements from schlieren and Pitot probe.