Nonlinear Aeroelasticity, Flight Dynamics and Control of a Flexible Membrane Traction Kite

Abstract

This chapter presents a computational method to describe the flight dynamics and deformation of inflatable flexible wings for traction power generation. A nonlinear Finite Element approach is used to discretize the pressurized tubular support structure and canopy of the wing. The quasi-steady aerodynamic loading of the wing sections is determined by empirical correlations accounting for the effect of local angle of attack and shape deformation. The forces in the bridle lines resulting from the aerodynamic loading are imposed as external forces on a dynamic system model to describe the flight dynamics of the kite. Considering the complexity of the coupled aeroelastic flight dynamics problem and the Matlab® implementation, simulation times are generally low. Spanwise bending and torsion of the wing are important deformation modes as clearly indicated by the simulation results. Asymmetric actuation of the steering lines induces the torsional deformation mode that is essential for the mechanism of steering. It can be concluded that the proposed method is a promising tool for detailed engineering analysis. The aerodynamic wing loading model is currently the limiting factor and should be replaced to achieve future accuracy improvements.