High Angle-of-Attack Pitching Moment Characteristics of Slender-Bodied Reusable Rocket

Abstract

The development of a fully reusable vertical-takeoff-and-vertical-landing (VTVL) rocket is indispensable for reducing space transportation costs. However, there are many technical issues associated with such vehicles, such as the safe execution of a turnover maneuver during return flight. It is known that a relatively desirable pitching moment characteristic for turnover can be accomplished by employing a slender body configuration, but the reason for this is not well understood. In this study, we carried out a delayed detached-eddy simulation (DDES) on the aerodynamic characteristics of such a slender-bodied reusable rocket for angles of attack between 0 and 180 degrees using unstructured compressible computationalfluid-dynamics (CFD). We also conducted inviscid calculations in order to distinguish the pitching moment contribution of the body configuration itself from the effects of viscosity and turbulence. It was found that two types of vortices were formed at 0-90 degrees, and also these vortices affected the pitching moment distribution. We also observed three types of vortices generated at 90-180 degrees. Combined with the results of the inviscid simulation, we concluded that the pitching moment characteristic is greatly impacted by the behaviors of these vortices and bubbles.

The cubic pitching moment coefficient of spin-stabilized projectiles

“…These negative coefficients were obtained through data reduction from free-flight tests of projectiles and thus can be used as the foundation for studying aerodynamic nonlinearities. In fact, several studies over the last decades [4][5][6][7][8][9][10][11][12][13] have focused on the nonlinear aerodynamic characteristics of slender bodies at high angles of attack. In Jernell's experiment, 4 aerodynamic characteristics of slender bodies with various fineness ratios were studied at very high angles of attack (more than 90 deg).…”

“…8. Aogaki et al 9 investigated the pitching moment characteristics of a reusable rocket with a fineness ratio of 5 by using the CFD method. On the other hand, from the approximate method perspective, research predicting C M α2 is relatively limited due to the complicated aerodynamic mechanism.…”