Robust optimization of variable-camber continuous trailing-edge flap system under multi-task profiles

A robust optimization method is described in this paper, focused on the optimization of a Variable-Camber Continuous Trailing-Edge Flap (VCCTEF) system for drag reduction under multi-cruise conditions. The optimization design for flaps deflection angles of VCCTEF system under different flight conditions can make the airplane improving the aerodynamics characteristics at multi-task profiles. The VCCTEF shape optimization, however, when based on rigorous CFD simulations, presents a significant computational challenge because of the high cost of repetitive analyses required. The construction of surrogate models and their utilization in the optimization process is one common way for tackling this challenge. In this paper, the Stochastic Kriging (SK) is used, extending the commonly used Deterministic Kriging (DK). Accounting for the intrinsic uncertainty of data, Stochastic Kriging and the optimization based on it are especially suited for addressing uncertain flight conditions as well as math modeling limitations. An optimization engine is presented that couples geometric shape synthesis with CFD simulations and an automated optimization process focused on the VCCTEF. A potential for drag reduction is shown even in the presence of uncertainties. And the results showed the reducing drag coefficients are different between different flight conditions.