EXPERIMENTAL INVESTIGATION OF A SUPERCAVITATING HYDROFOIL WITH UPPER SURFACE SPOILER FLAPS.
HYDRONAUTICS INC LAUREL MD
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Results are presented of lift and drag measurements performed on a 2 12 in. chord model of the BuShips Parent Supercavitating Hydrofoil without flaps and with full span spoiler flaps. The tests were conducted in the high-speed, variable pressure, free surface, circulating water channel. They cover angles of attack ranging from 2.5 to 12.8 degrees, vapor cavitation numbers from 0.075 to 1.38 and operating depths of 12 and 1 chord. The velocity during these tests was between 39 and 42 fps. Each of the three flaps parameters flap deflection, flapchord ratio, and flap trailing edge location, were varied in three steps while the other two parameters were held relatively constant. The results are presented in the form of graphs showing the variation of lift and drag with cavitation number and angle of attack. Graphs showing the reduction in lift due to the spoiler for each spoiler geometry and several cavitation numbers are also included. It is found that the upper surface spoiler flap is an effective way of reducing lift and that a discontinuity in lift at the ventilation inception angle can be avoided by proper selection of flap parameters. Author