The effect of the spacing between two centers of twin nozzles on the propagation of the Mach 0.8 twinjet is studied experimentally. The center-to-center spacings of the twin nozzles studied are equal to 3D and 5D (here, D is the nozzle exit diameter). The twinjets in parallel, inward and outward canting configurations are also studied. The inward and outward canting nozzles with a half angle of interception of 5°, 10°, and 15° are studied. For the inward canting, it is found that the peak Mach number is higher for the inward-canting twinjets than for the parallel and outward-canting twinjets. The interaction of twinjets diminishes with increase in the nozzle spacing.
Prakash et al. (Mon,) studied this question.