Low speed longitudinal aerodynamics of a blended wing-body re-entry vehicle

Abstract

This paper deals with the evaluation of low-speed longitudinal aerodynamic performances of a vehicle concept with an unconventional blended wing-body aeroshape. The spacecraft is intended as a multipurpose vehicle for future International Space Station payload and/or crew servicing and support, able to perform a lifting re-entry from Low Earth Orbit and to land on a conventional runway. The aeroshape features a high-sweep near double delta-shaped configuration, equipped with two functionally independent body flaps, which can be used for both longitudinal control (i.e., elevon mode) and lateral-directional control (i.e., aileron mode). Longitudinal aerodynamic force and moment coefficients are investigated with Computational Fluid Dynamics simulations carried out at Mach number equal to 0.3, typical of landing conditions. A comparison of low-speed performances for clean and flapped configurations is performed considering several vehicle attitudes and elevon deflection angles. High-lift performances of the aeroshape are discussed and related to the onset conditions of vorticity field at various angles of attack. Additionally, comparison of aerodynamic coefficients with classical delta-wing theory is also discussed, addressing the promising capabilities of the selected design to perform a glided horizontal landing. Finally, a description of vortex break-down phenomena occurring on the aeroshape at landing incidence is discussed, accounting for the aerodynamic coefficients in post-stall condition, also providing an overall picture of the longitudinal static stability of the vehicle.