Sensitivity analysis method for aeroelastic aircraft models

Abstract

A novel method has been developed for calculating gradients of aerodynamic force and moment coefficients for an aeroelastic aircraft model. This method is intended for use in preliminary-level aircraft design which typically involves computationally expensive aerodynamic and structural analyses. This method uses the global sensitivity equations (GSE) to express the aero-structural coupling in an aircraft model. In addition, a reduced-order modal analysis approach is employed to condense the coupling bandwidth between the aerodynamic and structural models. Coarse-grained parallel computing is applied to reduce the wall-clock computational time of the expensive aerodynamic analysis needed in this sensitivity analysis method. A supersonic transport aircraft model is examined in this study, subject to Mach 2.4 cruise flight conditions. Aerodynamic analysis is performed using a NASA-developed Euler/Navier-Stokes solver, and structural analysis is performed using commercial finite element analysis software. The GSE/modal analysis method is used to compute the sensitivity of the aerodynamic performance of the aircraft subject to perturbations in the angle-of-attack, wing sweep angle, and wing thickness. Good agreement is obtained between gradients computed with the GSE/modal analysis approach and the same quantities computed using a traditional, computationally expensive, finite difference approach. A cost analysis demonstrates that the GSE/modal analysis method is more computationally efficient than the traditional approach if gradients are needed for two or more aircraft design parameters.