A Study of the Interaction of Gaseous Jets from Transverse Slots with Supersonic External Flows

Abstract

The paper describes a study concerning the sonic injection of a gaseous jet through a transverse slot nozzle in a wall into an external flow which is uniform outside of a turbulent boundary layer. An analytic model of the flowfield has been constructed in which conservation of momentum is applied to a control volume at the jet nozzle exit. A series of flat-plate experiments was conducted with normal, sonic jets at external flow Mach numbers of 2.61, 3.50, and 4.54. Pressure data near separation and the plateau were in agreement with existing correlations. Comparisons of the trends predicted by the analysis with two-dimensional force data from these experiments and from other sources showed good agreement. Values of amplification factor, the upstream interaction force plus the jet thrust divided by the vacuum thrust of a sonic jet, of 2.9 to 3.2 were measured. The amplification factor is relatively insensitive to variations in external flow Mach number and variations in injectant gas properties. A correlation of data obtained from experiments with finite-span slots demonstrates that the effective jet penetration height and the slot span are the important characteristic dimensions of such flowfields.