Hydrodynamic study on the performance evaluation of flapping foils in open water condition

The hydrodynamic performance of a rigid foil inspired from the thunniform kind of propulsion is analyzed numerically. The hydrofoil is allowed to oscillate in pure pitch, pure heave and combined motion by varying the Strouhal number from 0.1 to 0.4. Both 2D and 3D analyzed are done for the combined motion of oscillation. The NACA0012 foil of 0.7m span and 0.141m chord is selected for the study. Qualitative observations of the wake field and trailing water jet is studied and presented using average vorticity and velocity contours. The parameters such as thrust coefficient, power coefficient, and efficiency are plotted against the Strouhal number. It is found that the maximum efficiency is achieved in Strouhal number range of 0.15–0.3.