Parameters Influencing the Effectiveness of Reaction Control Jets on the Basic Finner

Abstract

Reaction control jets provide a practical option to increase the acceleration rates of high-performance aerodynamic vehicles. Unfortunately, a designer or system engineer incorporating reaction control jets into a design cannot simply add the jet as a point force because it does not account for the change in force due to the modifications of the flowfield caused by the jet. The changes made to the flowfield can impact the forces and moments, enhancing, mitigating, or even reversing the desired force or moment, depending on a complex set of factors. This study examines the influence of different jet configurations, modifications to freestream parameters, and the presence of control surfaces on the body. It is shown that the proximity of the jet to the control surfaces has the most significant impact on the resulting force amplification. The emphasis is placed on differentiating between how the jet interacts with the body and fins. Ultimately, this shows that the interaction with the fuselage is consistent and self-similar, whereas the fins are primarily influenced by the jet blocking the flow and generating a shock that imparts high pressure on the control surface, increasing the force in the direction of the jet.