ON THE POSITION OF THE CENTRAL COMPRESSION SHOCK IN AN UNDEREXPANDED SONIC JET ISSUING FROM A SLOT NOZZLE.

One of the most important characteristics of the geometric structure of an underexpanded jet, the distance between the nozzle exit and the central compression shock (CGS), is the Mach disc in the axisymmetric case. While the geometric structure of underexpanded axisymmetric and plane jets has been studied in a sufficiently large range of changes in the degree of off-design, investigations devoted to the process of underexpanded jets issuing from finite width slots have been performed for only several nozzles. In this paper, the CCS location in the fundamental plane of underexpanded sonic jets issuing from slot nozzles with a between 1. 66 and 55. 5 is investigated experimentally for changes in the degree of jet off-design n (the ratio between the pressure at the nozzle exit and the pressure in the surrounding medium) form 1 to 110.