The Chesapeake Section of The Society of Naval Architects and Marine Engineers was presented an interesting paper on the Performance of Oscillating Foil Propulsion Systems by J. O. Scherer, senior research scientist of Hydronautics, Inc., at its December meeting.
In order to achieve practical levels of thrust, an oscillating foil propulsor must undergo large amplitude oscillations at relatively high frequency. The magnitude of the required oscillations is such that the classical small amplitude theories cannot provide adequate performance predictions for engineering purposes. The paper presented an analytical method for computing the forces and moments on a rigid foil of finite span undergoing large amplitude oscillations. The influence of foil stall and the induced slipstream were included.
The results of an extensive study were shown to be in good agreement with the theory.
Performance predictions for an oscillating foil propulsor suitable for use on a 15-knot, shallow-draft boat of 2,000-pound payload were presented. The results indicate that this type of propulsor can provide efficient shallow-water propulsion with a high degree of maneuverability.
A lively discussion followed the presentation. Of particular interest was a discussion by Robert Taggert of Robert Taggert, Inc., accompanied by slides, which commented on some parallels between the paper and studies which had been made concerning the means by which fish propel themselves.
The meeting, which took place at the Walter Reed Army Hospital Officers Club in Washington, D.C., was preceded by a social hour and dinner.
Principals at the December meeting of the Chesapeake Section, SNAME, were: J. O. Scherer, Hydronautics, Inc., author; Robert Taggert, Robert Taggert, Inc., Chesapeake Section chairman; Owen H. Oakley, Naval Ship Engineering Center, Chesapeake Section executive committee, and W. B. Morgan, Naval Ship Research & Development Center, meeting moderator.