Performance and Correlation Studies of the Buships Parent Hydrofoil at Speeds from 40 to 75 Knots

摘要

The hydrofoil was tested through a 1.44 to 12.44 deg range of angle of attack and depths of immersion of 0.5, 1.0, and 1.5 chords. Lift and drag measurements were made and cavitating flow conditions were determined from high speed photographs. The order of transition of cavitation with increasing speed was: base cavitation, partial upper surface cavitation, ventilation, and supercavitation. Abrupt transitions and overlapping of cavitation regions occurred. Lift coefficients were constant with base cavitation and complete ventilation. At low angles of attack, lift increased with decreasing draft. The hydrofoil vibrated during 65 percent of the tests. In the lowest frequency mode a relationship existed between speed and cycle length, independent of angle of attack, depth, and cavitation. (Author)