The impact of flapping trajectories on the induced thrust of a Single and tandem configuration flapping foil

The development of propulsion devices by using the propulsive mechanisms of aquatic animals such as fish is a challenging task. An attempt has been made to replicate the fishtailed motion that caused thrust in the current investigation. At a low Reynolds number of Re = 1173, the propulsive performance of NACA (National Advisory Committee for Aeronautics) 0012 flapping foils enduring distinct flapping trajectories (fishtailed and elliptical) is evaluated. A dynamic mesh arbitrary Lagrangian-Eulerian framework is used to understand the desired flapping motion of the foils while solving the flow via in-compressible Navier-Stokes equations. Along with the flapping trajectory, the effects of the Strouhal number (St), inter-foils distance (Lx), and phase angle (φ) between the foils on the produced thrust are examined. The results demonstrate that using tandem configuration flapping foil with elliptical and fishtailed flapping can significantly increase the induced thrust and propulsive efficiency.