Rainbow Schlieren Measurements in Underexpanded Sonic Jets from Axisymmetric Convergent Nozzles

摘要

A quantitative visual study of an underexpanded sonic jet issuing from an axisymmetric convergent nozzle by the rainbow schlieren deflectometry technique has been conducted to reveal a complex flowfield containing a Mach disk as well as Prandtl Meyer compression and expansion fans in the jet. A numerical simulation of underexpanded sonic jets has also been carried out to estimate the density flowfield inferred from the rainbow schlieren measurements. The structure of the underexpanded sonic jet from the rainbow schlieren measurements are compared with those from the numerical simulation.