Aerostructural optimization of the D8 wing with varying cruise mach numbers

The D8 “double-bubble” is a new transport aircraft configuration proposed by MIT that has the potential to provide large improvements in fuel efficiency. It has been studied at the conceptual level and in low-speed wind tunnel tests, but there was, up to now, no higher fidelity transonic design. In this study, we use the conceptual design definition as a starting point and develop a high-fidelity aero-structural optimization problem for the D8 configuration using the MACH framework. Via gradient-based optimization techniques with coupled RANS and shell FEA, the D8 is optimized at three different cruise Mach numbers (0.72, 0.78, 0.84). The preliminary results presented confirm that the planforms designed with the conceptual level tools perform well and as predicted, and that some small improvements can be gained from further optimization. In spite of its limitations, this work confirms the viability of the D8 wing-body in the transonic regime and provides preliminary transonic geometries for future work.