Three-dimensional, semi-cylindrical 1/3-scale bow models were droptested in the water impact generating tower to determine the characteristics of wave impact pressure acting on the bows of very large ships. The models were dropped onto the still water surface from various heights (5m at the maximum) at small relative angles (0,5, and 15 degrees) and with the total drop weight of 10 tons each time. From the test results, relations between the maximum impact pressure, relative bow-wave impact velocity relative stem-wave angle and radius of bow curvature were obtained. It was found that the maximum impact pressure would increase approximately as the square of the relative bow-wave impact velocity and would be affected more by the relative stem-wave angle than by the radius of bow curvature. No air-entrapment occurred even though the model was dropped at the relative stem-wave angle of 0 degree. The acoustic pressure was detected when the model hit the water surface at the relative angle of 0 degrees and at the relative impact velocity of 8m/sec. The impact pressure generated was the unsteady hydrodynamic pressure and, in the severest impact conditions, its rise was restricted by the acoustic pressure. The maximum impact pressures as measured on the surface of one rectangular section of the curved model plating were not distributed uniformly and simultaneously, as distinct from the uniformly distributed impact pressures, and were not considered to directly contribute to the structural response of the plating.

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  • Corporate Authors:

    Society of Naval Architects of Japan

    23 Shiba-kotohiracho, Minato-ku
    Tokyo 135,   Japan 

    Society of Naval Architects of Japan

    15-16, Toranomon, 1-chome, Minato-ku
    Tokyo,   Japan 
  • Authors:
    • Hagiwara, K
    • Yuhara, T
  • Publication Date: 1974-6

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Filing Info

  • Accession Number: 00071552
  • Record Type: Publication
  • Source Agency: Society of Naval Architects of Japan
  • Files: TRIS
  • Created Date: Nov 12 1974 12:00AM