プロペラSurface forceが船体におよぼす影響について

その1 艦艇におけるプロペラ附近の変動水圧およびそれによつて生ずる船底外板応力の実船計測例

抄録

The varying hydro-dynamical pressure near the rotating propeller, named “surface force” by F. M. Lewis, was actually investigated on the twin-screw destroyer. Measured pressure variations consist of the blade frequency component and other higher frequency components. The autocorrelation functions and the frequency spectra were taken from the record of pressure variations, and it was learned that nearly all of the higher frequency components were as irregular as noise. Pressure variation amplitudes near the tip of propeller excluding such noise-components were in good agreement with the amplitudes estimated from the model test results.
Also, the varying stresses in the bottom shell near the tips of propeller were measured by means of the wire strain gauge, and it was noted that the measured stress variations roughly coincided with the estimated ones calculated from the measured pressure variations.
Several problems of the flexural vibration of ship's hull forced by the pressure variation, the local vibration and the determining the thickness of the bottom shell in the vicinity of propellers etc., may be presented from our investigation on this subject. Regarding these problems, further reports shall be published.