Secondary Gas Injection into Rocket Nozzles through Ports Mutually at Right Angles

Abstract

The side force produced by gas injection through a single port into the supersonic regime of a rocket nozzle is composed of the natural reaction of the fluid leaving the port and the force due to pressure fields set up within the nozzle by the interaction of the secondary and primary flows. The obstruction presented to the main flow by the entering secondary fluid produces a shock system originating from the vicinity of the injection port. The pitch and yaw of a rocket can be controlled by simultaneous secondary gas injection from two ports mutually at right angles. With two ports operating, the respective shock wave systems produced can interact and hence cause an alteration of the side forces which would be produced if the ports were operating independently.