Supersonic Aircraft Drag Reduction Optimization Design in a Wide Speed Range Based on the Adjoint Method

For the new generation of supersonic passenger aircraft, it is essential to simultaneously consider the aerodynamic characteristics of both supersonic and transonic speeds to meet engineering requirements. This study utilizes a Computational Fluid Dynamics (CFD) solver based on the Reynolds-averaged Navier-Stokes (RANS) equations, incorporating Free Form Deformation (FFD) parameterized modeling technique, grid deformation technique based on Inverse Distance Weighting (IDW) interpolation algorithm, and gradient optimization algorithm (Sequential Quadratic Programming, SQP) to establish a gradient-based aerodynamic adjoint optimization design system. The research focuses on aerodynamic drag reduction optimization with volume constraints on the wing, aiming to minimize the overall aircraft drag. The design outcomes show an 8.43% drag reduction at supersonic conditions and a 2.68% drag reduction at transonic conditions. At supersonic speeds, shock waves appear at the leading edge of the inner wing section, the adverse pressure gradient weakens in the outer wing section, pressure recovery becomes smoother, and shock wave intensity significantly decreases. At transonic speeds, minimal changes in wing pressure distribution ensure lift for the supersonic aircraft during transonic flight.