Numerical simulations employing the dynamic mesh method were performed to investigate the unsteady aerodynamics of variable-sweep wings during morphing. Quasi-steady and unsteady aerodynamic characteristics were compared, and the effects of key operating conditions (freestream velocity, angle of attack, morphing period, wingspan, chord length) on unsteady aerodynamics were analyzed. To enable the rapid prediction of unsteady aerodynamics, a Kriging surrogate model was established and validated against high-fidelity CFD results. The results indicate that unsteady effects manifest as hysteresis loops in aerodynamic coefficients within the morphing cycle. The wing morphing period, angle of attack, freestream velocity, and wingspan have a pronounced impact on the unsteady aerodynamic characteristics, whereas the effect of chord length is negligible. Reduced morphing periods, increased angles of attack, and increased wingspans amplify the hysteresis loop size and enhance the unsteady effects. An increase in the freestream velocity intensifies unsteady effects in the subsonic flow, while it attenuates unsteady effects in the supersonic flow. Compared to direct CFD simulations, the Kriging model for unsteady aerodynamic characteristics prediction achieves a 97% improvement in overall computational efficiency, while its predicted hysteresis loops are in good agreement with CFD results in both trend and magnitude, with an average prediction error below 4% and a maximum error of less than 6%. The Kriging surrogate model developed in this study offers substantial practical value for engineering applications by meeting the demand for rapid aerodynamic computation in the concept design phase for morphing aircraft.

Truss-braced wings (TBWs) feature higher aspect ratios with a lighter weight and lower bending moment than conventional wings. These wings show significant potential for performance improvements in terms of fuel efficiency. However, additional configurations of these wings also present nonlinear problems and challenges in aeroelastic designs. This paper investigates the static response of a TBW with a high aspect ratio, specifically focusing on the impact of the spanwise joint location on aeroelastic characteristics. The TBW is modeled by nonlinear beam elements and the unsteady vortex-lattice method (UVLM). The results show that the bending deformation is effectively reduced by the truss member and the deformation is impacted by the location of the spanwise joint connected to the main body.

High-aspect-ratio wings may exhibit large deformations and geometrical nonlinearities. A novel framework is proposed to investigagte these nonlinear aeroelastic behaviors, enabling the prediction of flutter and limit cycle oscillations. The nonlinear solver of MSC.Nastran is accommodated to update finite elements subject to large deformations. An unsteady vortex-lattice method is coupled with the finite elements. The framework is validated against wind tunnel tests, showing reasonable agreements for flutter velocity and frequency. The framework also successfully predicts limit cycle oscillations, which cannot be evaluated by linear simulations. Thus, the present method enhances the understanding of aeroelastic stability in high-aspect-ratio wings.