Executive Summary : | The project entails the study of flapping mechanism of wings of birds, insects and fins of fishes in order to design optimized bio-inspired engineering vehicles. The comprehensive understanding of the flow dynamics of these natural creatures will give an insight about the way these animals flap their wings/fins and maintain high propulsive efficiency and stability in their locomotion. Of particular interest to the present work is the tandem wing configuration (observed in a flock of birds, swarm of bats, and schools of fish) where the creatures fly/swim in-line in a group. Simplifying the wing/fin geometry to that of a foil, it is imperative to study this foil configuration and the effect of flapping motion on the propulsive performance of the system. The flapping motion consists of pitching (rotation) and heaving (translation) motion. The of the project is to fill the loopholes in the literature pertaining to the effects of gap between the foils, kinematic parameters such as pitch and heave amplitude & flapping frequency, and the effect of flexibility and morphing on propulsion. The present proposal builds upon the research work carried out by the Principal Investigator and is an attempt to comprehensively understand the flow dynamics of tandem flapping foils. To begin with, the project will involve carrying out numerical experiments and computations to investigate the effect of pitch and heave amplitudes and the flapping frequency on the propulsion for rigid foils. Thereafter, the effects of flexibility will be incorporated with the help of passive deformation as well as active morphing of the foils. Fully coupled fluid-structure interaction computations will be carried out to comprehend the morphing and flexibility effects on the performance of the tandem system. The research findings and suggestions from the project will be beneficial in the development of bio-inspired flying/marine vehicles based on flapping dynamics, which could be a game-changer for military surveillance, offshore station-keeping and search & rescue missions. |