Bioinspired Flapping Foil With Trailing Edge Flap For Remotely Operated Vehicles (ROVs)

Highly efficient propulsive mechanisms of aquatic swimming creatures could serve as inspiration for developing new propulsion methods where it exceeds the performance of present-day thrusters and propellers for ASVs, AUVs, and ROVs. The advantages of eco-friendly propulsion combined with a lesser wake could be advantageous for marine vehicles' stability and maneuvering. As a result, we need to improve our knowledge of fish or dolphin swimming hydrodynamics and their fluid-structure interaction to develop benchmark designs for new propulsion methods. Flapping foil thrusters for propulsion has sparked much interest in recent years. AUVs, ASVs, and ROVs vehicles could greatly benefit from this technology. In dolphin swimming kinematics, the flapping foil thruster is an essential component. This research aims to understand better the hydrodynamics and fluid-structure interaction of flapping foils subjected to heaving and pitching motions. In the present study, the bio-inspired flapping foil thrusters fitted with trailing edge flaps are studied experimentally using flow visualization techniques such as 2D particle image velocimetry (PIV). The time average vorticity contours and instantaneous velocity contours are presented in this study. The flapping foils with trailing edge flaps are immersed in a free stream of uniform flow speed varying from 5 to 10 cm/s. The operating Reynold number (Re) range is 500 to 4300. The Strouhal number range is 0.2 to 0.3. This study also investigated the effect of flapping foil without trailing edge flaps using 2D numerical simulations. By simulating the wake structure and its evolution, the present study aims to understand the vortex shedding mechanisms of flapping foil with or without trailing edge flaps, determining thrust and propulsive efficiency. The vortex shedding mechanisms for both the foils are presented and discussed in detail.