and Suleman A., “ A Review on Non-Linear Aeroelasticity of High Aspect-Ratio Wings,” Progress in Aerospace Sciences, Vol. 89, Feb. 2017, pp. 40–57.
H., “ On the Importance of Aerodynamic and Structural Geometrical Nonlinearities in Aeroelastic Behavior of High-Aspect-Ratio Wings,” Journal of Fluids and Structures, Vol. 19, No. 7, 2004, pp. 905–915. and Venkatramani J., “ Response Analysis of a Pitch–Plunge Airfoil with Structural and Aerodynamic Nonlinearities Subjected to Randomly Fluctuating Flows,” Journal of Fluids and Structures, Vol. 92, Jan. 2020, Paper 102820. and Dimitriadis G., “ Dynamic Stall and Stall Flutter Simulations for a 2D Airfoil Using Viscous-Inviscid Coupling,” 54th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, AIAA Paper 2013-1839, 2013. and Dimitriadis G., “ Unsteady Navier-Stokes Simulation of Low-Reynolds Stall Flutter,” 50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition, AIAA Paper 2012-0037, 2012. and Chantharasenawong C., “ Assessment of Added Mass Effects on Flutter Boundaries Using the Leishman–Beddoes Dynamic Stall Model,” Journal of Fluids and Structures, Vol. 26, No. 5, 2010, pp. 814–840. and Chantharasenawong C., “ An Assessment of Some Effects of the Nonsmoothness of the Leishman–Beddoes Dynamic Stall Model on the Nonlinear Dynamics of a Typical Aerofoil Section,” Journal of Fluids and Structures, Vol. 24, No. 1, 2008, pp. 151–163. S., “ Nonlinear Aeroelastic Analysis of Airfoils: Bifurcation and Chaos,” Progress in Aerospace Sciences, Vol. 35, No. 3, 1999, pp. 205–334. Livne E., “ Future of Airplane Aeroelasticity,” Journal of Aircraft, Vol. 40, No. 6, 2003, pp. 1066–1092. Simulation results demonstrate the effectiveness of the designed controller. A Lyapunov function is established to prove the stability of the closed-loop system.
#INSTALL SOLIDWORKS FREE UCF AIAA UPDATE#
Considering such uncertainties, an adaptive controller with an estimation update law is designed to stabilize the airfoil subjected to gusts. Next, an uncertain N th-order polynomial stiffness for pitch and uncertain structural damping (modeled by viscous damping) coefficients for all DOFs are assumed. It was found that a proportional–derivative controller based on the partial feedback linearized system could effectively alleviate oscillations induced by gusts at flow velocities below and above the linear flutter speed.
Numerical results show that the airfoil may become unstable via a Hopf bifurcation at a flow velocity well below the linear flutter speed if the structural damping is not sufficiently high, it may also undergo chaotic motion.
The nonlinear dynamics of the system without control and parametric uncertainty, where a cubic stiffness for pitch and a linear stiffness for plunge are considered, is examined. A flat spot or dead-zone-type stiffness is used for modeling the flap hinge free play. The motion of the airfoil is modeled by three degrees of freedom (DOFs), namely, pitch, plunge, and flap. This paper presents the dynamics and adaptive control of an airfoil with structural stiffness and damping uncertainties, which is subjected to atmospheric gusts.
0 kommentar(er)
