Efficient Modal Design Variables for Optimization of Aero-Elastic Wing

Efficient multi-disciplinary optimization is presented for aero-structural wing optimization using efficient low-dimensional modal design variables. Orthogonal aerofoil design variables are derived in the geometric space via singular value decomposition. Orthogonality of design variables leads to a well-conditioned design space and encourages positive optimizer convergence. These are applied in a sectional fashion for fixed planform drag minimization of a flexible transonic wing. Shock-free solutions are demonstrated for the rigid wing, indicating suitability of the aerofoil modes for sectional-based wing optimization. However, these wings have poor performance when deformed under flight loads, hence full aeroelastic performance is taken into account. Encouragingly, shock-free solutions are again found. Loading is shifted outboard, leading to increased tip-deflection. Monotonic improvement in objective with increase in dimensionality is also observed.