Supersonic Forward-Swept Wing Design Using Multifidelity Efficient Global Optimization

In this paper, the ability of the forward-swept supersonic wing to simultaneously reduce aerodynamic drag and sonic boom under cruise conditions is investigated via the optimization of airfoil distribution. The forward-swept wing is superior to the conventional backward-swept delta wing for reducing sonic booms. To realize optimum aerodynamic characteristics, airfoil distributions for the forward-swept and backward-swept wings were acquired and compared for low-drag, low-boom wing abilities. For sonic boom evaluations, the augmented Burgers equation and multipole analysis were applied to near-field pressure distributions calculated by Euler simulations of both configuration samples. This process was time-consuming, so a multifidelity approach was introduced with a multi-additional sampling. Low-drag and low-boom solutions were obtained for both planforms; the forward-swept wing was found to reduce sonic boom and aerodynamic drag more efficiently than the backward-swept wing. Based on functional analysis of variance, different design variables were noted to contribute toward reductions of the various objective functions. In case of sonic boom reduction via comparison of the low-boom solutions, for the given airfoil geometries at the wing tips for the forward-swept and backward-swept wings, the former had a larger twisted-down angle and the latter had a stronger camber shape.