Roll Moment Characteristics of Supersonic Flight Vehicle Equipped with Asymmetric Protuberance

Most of flight vehicles have various protuberant devices on their surfaces, but asymmetry in their positioning with respect to the body axis can affect aerodynamic characteristics of vehicles, particularly roll moment. Thus, it is important in rocket development to clarify the effects of the protuberances on the vehicle aerodynamic characteristics. In this study, as a basic research, we systematically investigated such effects using CFD, by changing the positions of a protuberance. As a result, the roll moment increased nearly linearly with angle of attack (= α ), but its trend was different in protuberance locations, particularly when arranged near the center-of-gravity. In positioning there at α = 20 °, the wake vortex center moved farther away from protuberance compared with α = 15 °, then the pressure decline at its wake side was suppressed, and thus, the pressure difference between its upstream and downstream sides became smaller. As a consequence, the roll moment did not arise linearly, but decreased at α = 20 °.