Two-dimensional quantitative visualization of isolator shock trains by rainbow schlieren deflectometry

摘要

The rainbow schlieren deflectometry is effective in studying quantitatively the density fields in shock-containing free jets at high precision and high spatial resolution. However, there has been no practical application of rainbow schlieren deflectometry for shock trains in a confined duct. Therefore, in the present study, the rainbow schlieren deflectometry is applied to the flow field including a shock train in a constant-area duct where just upstream of the shock train the freestream Mach number is 1.34, the unit Reynolds number is 5.39 × 10~7 m~(-1), and the boundary layer displacement thickness is 0.149 mm. As a result, a two-dimensional density field of the shock train is for the first time quantitatively displayed and the fine structure of the shock train is illustrated as a color gradation representation.