Browsing by Author "Schiebe, F. R."

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    Lift and Drag on Surface-Peircing Dihedral Hydrofoils in Regular Waves
    (St. Anthony Falls Laboratory, 1960-09) Straub, Lorenz G.; Schiebe, F. R.
    Experimental measurements were made of the lift and drag of a restrained surface-piercing dihedral hydrofoil in regular head and following seas. Two velocities and a variety of wave lengths and amplitudes were used. The oscillatory lift was predicted with fair success using linearized theory as developed by Ogilvie. The experimental forces were observed to contain harmonic distortion, and comparison of the second harmonic component obtained from nonlinear quasi-steady theory indicated that the calculated values were too low. No theory was available for comparison with the oscillatory drag forces. Tests with a restrained tandem dihedral configuration in smooth water indicated that the performance ratio of the aft foil could be considerably increased for a particular separation of the foils. The optimum separation increased with increasing velocity. A brief series of tests were made in head seas using the optimum foil separation, and little difference between the tandem foils and single foil was noted for the oscillatory lift component.
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    Studies of the Flow Characteristics of a Compressible, Bubbly Mixture about Supercavitating Bodies and in a Converging-Diverging Nozzle
    (St. Anthony Falls Hydraulic Laboratory, 1964-04) Schiebe, F. R.; Wetzel, J. M.; Foerster, K. E.
    Experimental studies have been made to determine the effect of a compressible, air-water mixture on the drag characteristics of a cavitating body. Data are reported for a series of conical bodies of various slenderness ratios for free stream Mach numbers up to 0.7. Results indicate that the drag coefficient increases with Mach number, although in general not as rapidly as for a non-cavitating body. It was possible to apply Gothert's rule to adequately predict the drag coefficient up to Mach numbers of about 0.6. A brief study was also conducted to study the flow characteristics of an air-water mixture in a converging-diverging nozzle. Supersonic flow was obtained and shock waves were observed downstream of the throat. Measured throat pressures for choked flow were somewhat higher than those calculated from homogeneous mixture theory.