مبانی مقدماتی از طراحی و ساخت و معماری بالباسبو
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Introduction
NEARLY 90 YEAHS AGO, H. E. Froudt' 1 1 12 interpreted the lower resistance of a torpedo boat, after f illing of a torpedo tube, as the wave reduction effect of the thickening of the bow due to the torpedo tube. D. W. Taylor was the f irst who recognized the bulbousbow as an elementary device lo reduce the wave making resistance. ln 1907 he f itted the battleship Delaware with a bulbous bow to increase the speed at constant power. ln spite of great activities in the experimental field to explore its potential , 70 years had lo pass before the bulb finally asserted itself as an elementary device in practical shipbuilding. A suitably rated and shaped bulb affects nearly all of the prop erties of a ship. Especially for fast ships, the use of a bulb allows a departure from hitherto accepted design principles f or the benefit of a better underwater form. The higher building costs are the only disadvantage. The protruding bulb form affects hydrodynamically a variation of the velocity f ield in the vicinity of the bow, that is, in the region of the rising ship waves. Primarily the bulb at tenuates the bow wave system, which usually is accompanied by a reduction of wave resistance. By smoothing the flow around the forebody, there is good reason to believe that the bulb tends to reduce the viscous resistance too. Therefore, the beneficial action of a protruding bulb depends on the size, the position, and the form of the bulb body.