Propulsion enhancement of flexible plunging foils: Comparing linear theory predictions with high-fidelity CFD results

The fluid–structure interaction of a flexible plunging hydrofoil immersed in current is solved numerically to analyze its propulsion enhancement due flexibility at Reynolds number 10000. After validating with available experimental data, the code used assess analytical predictions from linear theory. We consider large stiffness ratios, high thrust by flexibility, and small mass ratios appropriate for underwater propulsion. maximum observed first natural frequency, accurately predicted theory algebraically. magnitude over-predicted as flapping amplitude increases. For Strouhal numbers flow becomes aperiodic, which enough amplitudes happens frequencies below frequency. But even these numbers, predicts quite well frequency optimal propulsive efficiency. conclude that constitutes reliable useful guide design flapping-foil thrusters, we provide practical chart easily select function actuation point, hydrofoil.