Interferometric study of the initial region of two-dimensional supersonic nitrogen jets over a wide range of flow-defect number

The effects of flow-defect number on the structure of the density distribution in the initial region of a steady supersonic nitrogen jet are studied. The jet flowed through a flat nozzle designed so that M = 4, and the flow defect number varied from 1200 to 0.6. The nitrogen jet was forced out by reflection of a shock wave from the end of a shock tube into a pressure chamber, which was filled with nitrogen to the pressure giving the required flow defect number. The experiments were performed using a polarizing shift interferometer designed around a standard IAB-451 interferometer. The effects of the boundary layer along the nozzle walls on the flow were ascertained, in addition to effects of gas viscosity, flow turbulence, and steady and nonsteady wave processes at small values of the flow-defect number.