Kazuhiko Yamada

As a new atmospheric-entry technology, the research and development of atmospheric-entry vehicles with flexible aeroshells has been rapidly expanding. A lightweight and large-area flexible aeroshell enables a low-ballistic coefficient of flight and an efficient aerodynamic deceleration, thereby reducing aerodynamic heating and communication blackouts. Aerodynamic forces deform flexible aeroshells, altering their aerodynamic characteristics. However, the manner in which the attitude characteristics change when the aeroshell undergoes significant shape deformation is not well understood. In this study, the attitude and aerodynamic characteristics of a flexible aeroshell were clarified using wind tunnel tests at a given angle of attack and corresponding fluid–structure interaction (FSI) analysis. The FSI analysis method is based on a partitioned coupling method for large-scale parallel computers that use open-source software. The FSI analytical model reasonably explained the aeroshell deformation and aerodynamic coefficient behavior, and its validity was confirmed by wind tunnel experiments. The shape deformation of the flexible aeroshell weakened its restoring motion, thus exhibiting attitude instability compared with those prior to deformation.