Coupling Dynamic Stall with Lifting-Line Theory for Gust and Maneuver Analysis

This study presents a unified aeroelastic modeling framework that augments classical lifting-line theory (LLT) with a Goman–Khrabrov (GK) dynamic stall model to capture unsteady aerodynamic and structural interactions under gust and maneuvering conditions. The model formulates the coupled aeroelastic system in state-space form, integrating structural degrees of freedom (plunge and pitch), aerodynamic lag states from Wagner and Küssner approximations, and internal separation dynamics through the GK model. The circulatory lift coefficient is reconstructed by combining contributions from structural motion, aerodynamic memory effects, and dynamic stall behavior, enabling a compact representation driven by gust and maneuver inputs. Flutter boundaries are identified via eigenvalue sweeps tracking the maximum real part as a function of airspeed, while time-domain simulations are used to assess transient responses under representative excitations. Model predictions are validated against a reduced doublet-lattice-method-like formulation and finite-element aeroelastic results (FEMAP/NASTRAN) for modal characteristics, as well as high-fidelity computational fluid dynamics simulations (ANSYS Fluent) for lift time histories. The results demonstrate that embedding GK dynamics within an LLT framework improves the prediction of lift amplitude and phase near stall while maintaining computational efficiency. The proposed approach provides a practical low-order tool for flutter and gust-response analysis of finite wings subject to unsteady, nonlinear aerodynamic effects.