Publication Detail

Flapping Foil Propulsion for Cruising and Hovering Autonomous Underwater Vehicles

Victor Polidoro

This thesis describes the design, construction, and testing of an autonomous under-water vehicle capable of high precision positioning and hovering using °apping foils
as actuators. The vehicle is 2 m long with an approximate displacement of 157 kg.
Four °apping foils, each actuated by two motors, performing a two degree of freedom
angular motion (roll and pitch motion) provide the necessary forces for maneuvering
and propulsion. The design of the actuators is based on an extensive hydrodynamic
database for two and three dimensional foils developed at the Testing Tank and the
Propeller Tunnel facilities. The foils have dimensions 0.4 m span and 0.1 m chord
and are capable of producing peak lift forces up to 100 N, peak thrust forces up to
70 N, and mean thrust forces up to 37 N. Flapping foils can provide large forces (up
to an order of magnitude larger than steadily translating foils) very rapidly.
Experiments were performed with an individual foil actuator over a range of foil
sizes (s=c = 6, 5, 4, 3) and wake widths (1:4 · h0=c · 6:3). Planform area thrust
coe±cients of 7.2 were recorded at a Strouhal number of 1.2. The coe±cient of thrust
was found to be a strong function of the Strouhal number and maximum angle of
attack and a weak function of the wake width in this regime. The size of the foil was
the primary factor controlling the trade o® between the magnitude and bandwidth
of the thrust forces produced.

type: Full theses / dissertations

Parent Project

Project No.: 2001-RT-2/RD-13
Title: Biomimetic Rigid Hull Vehicle with Flapping Foils for Enhanced Agility in the Surf Zone and Cluttered Environments

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