Robust Optimization of Variable-Camber Continuous Trailing-Edge Flap Static Aeroelastic Action

Abstract

A robust optimization method is described in this paper, focusing on the optimization of a variable-camber continuous trailing-edge flap system for drag reduction in transonic cruise. The variable-camber continuous trailing-edge flap, through the rich combination of shapes it can attain, has the potential to provide greater design and operation freedom than conventional flap systems as well as greater efficiency in drag reduction and performance improvement. The deformation shape optimization of such a system, however, when based on rigorous computational fluid dynamics simulations, presents a significant computational challenge because of the high cost of repetitive analyses required. The construction of surrogate models and their use in the optimization process is one common way to tackle this challenge. Here, stochastic kriging is used, extending the commonly used deterministic kriging. Accounting for the intrinsic uncertainty of data, stochastic kriging and the optimization based on it are well suited for addressing uncertain flight conditions as well as math modeling limitations. An optimization process for the variable-camber continuous trailing-edge flap system that couples shape synthesis with high-fidelity aerodynamic simulations, accounting for static aeroelastic interactions and load distribution constraints, is presented. A potential for robust optimal drag subject to flight Mach number uncertainties is shown.