Force and hydrodynamic efficiency measurements of a three-dimensional flapping foil
Author(s)McLetchie, Karl-Magnus Weidmann
Massachusetts Institute of Technology. Dept. of Mechanical Engineering.
Michael S. Triantafyllou and Douglas P. Hart.
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Investigations into unsteady flapping foil propulsion have shown that it is an efficient and high thrust means of propulsion. Extensive work has been done to optimize the efficiency of two-dimensional flapping foils, varying both the kinematics of the motion and the flexibility of the foil. However, no thorough investigation into the hydrodynamic efficiency of three-dimensional flapping foils has been made. In this thesis, experimental hydrodynamic efficiency measurements and force measurements of a three-dimensional flapping foil are presented. These measurements were made by mounting a small, six-axis dynamometer directly onto the foil shaft of a flapping foil module. The module uses two computer controlled servo motors to actuate a foil in a sinusoidal pitch and roll motion, similar to the motion of a penguin's wing. The measured thrust coefficients compared well to previous experimental results, and the on-shaft dynamometer proved to be a valuable sensor. However, the experimental apparatus must be modified before reliable efficiency results can be made for the entire range of kinematics.(cont.) Once these improvements are made, a thorough investigation into the effects of foil geometry and flexibility can be done to find the optimum efficiency parameters of a three-dimensional flapping foil. These optimum efficiency parameters will be valuable for the development of flapping foil vehicles.
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Includes bibliographical references (p. 69-70).
DepartmentMassachusetts Institute of Technology. Department of Mechanical Engineering; Massachusetts Institute of Technology. Department of Ocean Engineering
Massachusetts Institute of Technology
Ocean Engineering., Mechanical Engineering.