An Experimental Study on the Effect of Submergence on a Vertically Oscillating Hydrofoil at Zero Translational Velocity

Abstract:

This paper presents experimental results for the hydrodynamic forces on several different bodies oscillating in the vicinity of the free surface. Firstly, results for two horizontally symmetric bodies, a flat plate of finite thickness and a cylinder, are presented. Results show that these two different shaped bodies react in different ways with the free surface and are likely to have different added mass associated with them. Secondly, results for two thrusting bodies, a NACA0012 symmetrical foil and a NACA4415 cambered foil, show that the free surface amplifies the thrust produced by a vertically oscillating foil. Results showing the effects of spanwise flow are also presented and indicate spanwise flow is negligible at zero translational velocity and so the use of endplates of the foils was unnecessary. The conclusion of these experiments is that a submergence of 5 chord lengths is sufficient for the horizontal and vertical forces on the vertically oscillating objects to be unaffected by the free surface.

• Periodical: Applied Mechanics and Materials (Volumes 226-228)
• Pages: 459-465
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.226-228.459
• Online since: November 2012
• Authors: Rajan Fernandez, Keith Alexander
• Keywords: Added Mass, End Plates, Flat Plate, Hydrofoil, Oscillating Foil, Virtual Mass, Wing

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