Study on an Oscillating Wing Propulsion Mechanism : 2nd Report, Case of Two-Dimensional Symmetry Wing

Abstract

Among aquatic animals, tuna, mackerel and dolphin seem to have achieved a high-speed and high-efficiency swimming method. Their measured speeds are sometimes higher than those of the theoretical estimations. We investigate the propulsion mechanism by modeling their caudal fin movement as a simple mechanism of two hinges, a rigid caudal arm and a rigid wing. The mechanism enables simultaneous wing heaving and pitching motions. In this study we determine the most effective motion of the wing in the case of an NACA 0015 wing section profile. The calculation result showed that the wing profile was much more effective than a flat plate wing profile. Furthermore, we present an analysis of the behavior of characteristic quantities of oscillating wing mechanism at large swimming number.