Thrust enhancement mechanism of a single and tandem flapping foil following an elliptical flapping trajectory

Abstract

Abstract Flapping foil devices have drawn considerable attention as a new means of thrust generation devices. The present study investigates the hydrodynamic performance mechanism of a single and tandem flapping foil undergoing different flapping trajectories with two different phase angles, 0° and 180°. The hydrodynamic efficiency, such as propulsive efficiency and wake structure of the single and tandem hydrofoil, are examined using computational methods. The effect of Strouhal number (St) and stream-wise gap (Gx) was also discussed along with the flapping trajectory. The results show that by implementing the new flapping trajectory, the induced thrust of the trailing foil can be enhanced up to 45% compared to the simple flapping. This study shed new light on improving biomimetic propulsion devices, as it aims to enhance the elicited thrust of the hydrofoil.