Numerical Analysis on Reusable Rocket Aerodynamics with Reduced-Yaw-Force Configurations

It is known that aerodynamic characteristics of a slender body vary substantially at high angles-of-attack (AoAs), and then, will have strong impacts on its flight. For, example, the yaw force makes flight unstable. In this study, we investigated the relation between the yaw force and the configuration, and details of flowfield around the slender-bodied-vehicle numerically. The configuration consisting of “nose cone” and “square aftbody” parts was employed as the baseline, and then, compared with other three configurations having different fineness ratios. According to our computed results, in the case of 50 degrees of AoA, the longer the model became, the more asymmetry appeared: yaw force and asymmetry were found to be attributed not only to the length of the body, but also to the nose bluntness. On the contrary, in the case of 140 degrees, the shorter the model became, the more asymmetry appeared. Furthermore, the large nose bluntness increased CY. Interestingly, this trend is totally opposite to that observed at 50 degrees. It had been considered that the large nose bluntness and the small fineness ratio can reduce asymmetry and CY, however, this study showed that it is not true in the case over 90 degrees, due to complex wake flow structure discovered in the present numerical simulations.