MOTION DAMPING OF MARINE AEROFOILS - A COMPARISON OF EXPERIMENTAL MEASUREMENTS WITH THEORY

A programme of research was carried out at University College London (UCL) between 1986 and 1989 to investigate the motion damping characteristics of wind energy devices. This paper follow an earlier paper by the same authors reporting an investigation into the theoretical aspects of the motion damping of ships fitted with marine aerofoils, in which an analysis was developed to evaluate aerodynamic roll and pitch damping as functions of various parameters. Calculations were carried out using linearised quasi-static lifting surface theory. At a later stage in the UCL research programme, experimental measurements of these derivatives were obtained and some of these are reported here. Fitting curves to the experimental data of the same form as the theoretical curves shows that the experimental results follow the theory in principle, although the coefficients are slightly different. Therefore, all conclusions drawn from the theoretical results in the previous paper are still valid, and the theory can be made realistically accurate by the inclusion of a dynamic load factor.