Inline motion in flapping foils for improved force vectoring performance

Abstract

In this thesis, I study the effect of adding in-line oscillation to heaving and pitching foils using a power downstroke. I show that far from being a limitation imposed by the muscular structure of certain animals, in-line motion can be a powerful means to either substantially augment the mean lift, or reduce oscillatory lift and increase thrust. Additionally, I show that the use of a model-based optimization scheme, driving a sequence of experimental runs, allows the ability for flapping foils to tightly vector and keep the force in the desired direction, hence improving locomotion and maneuvering. I employ Particle Image Velocimetry (PIV) to visualize the various wake patterns of these foil trajectories and a force transducer to evaluate their performance within a towing-tank experiment.