Active Flutter Suppression in Transonic Flow Based on Linearized RANS CFD

Abstract

Active flutter suppression is recognized as a potential technology that may enable more efficient aircraft, and research activities to evaluate its feasibility in the transonic regime are flourishing. Aeroelastic models for control traditionally use the Doublet Lattice Method (DLM) to account for unsteady aerodynamics. However, DLM cannot capture wing thickness effects, steady state dependency, as well as nonlinear transonic flow phenomena which lead to complex flutter behavior as typified by transonic dips. To address these shortcomings, this work employes linearized RANS CFD to provide a more accurate representation of the unsteady pressure field, thereby improving any subsequent control activity. The workflow, encompassing aeroelastic modeling, flutter suppression control synthesis, and post-synthesis controller verification, is illustrated for both the conventional DLM-based approach and the proposed CFD-based approach, using the NACA 64A010 airfoil and a benchmark 3D case, the BACT wing. The superior performance of the CFD-based approach in transonic flow conditions is clearly demonstrated.