Investigation of supersonic plane underexpanded jets by the laser schlieren method

The laser schlieren technique was used to study supersonic plane underexpanded jets of a shock-heated gas, flowing through a transonic nozzle into a rarefied medium. The study considered jets of CO2 and the 30% CO2 + 70% N2 mixture with initial temperatures of 1250-2070 K and pressures of (6.2-12.9) x 10 to the 5th Pa. For the central streamtube of the jet, density gradient distribution functions were obtained, which were used to determine the density profiles. It is shown that the jets investigated were nontwo-dimensional. The magnitude of the boundary layer formed on the surfaces confining the jet was evaluated.