THREE RECENT PAPERS BY JAPANESE AUTHORS ON THE EFFECT OF BULBS ON WAVE MAKING RESISTANCE OF SHIPS
The first paper, TANK EXPERIMENTS ON THE WAVE MAKING CHARACTERISTICS OF THE BULBOUS BOW, is aimed at the experimental determination of the existing conflict with regard to the 'actual' phase-difference between the bulb waves and the hull waves. The wave analysis procedure is applied for the first time. The conclusion is that the theoretical treatment of the bulb which is introduced by Havelock and Wigley can be practically approved. Its corresponding system of singularities is represented by the combination of an isolated doublet with a continuous source distribution. The former has a positive and therefore the same sense as the latter in hull form characteristics, but has a negative and therefore the reverse sense in wave-making characteristics. This is the true reason why the wavemaking resistance is sometimes reduced remarkably with the bulbous form whose displacement is larger by its bulb than the original form. The second paper, A STUDY ON THE WAVELESS BOW, describes the processes of verification, especially for bow waves, to the above-mentioned theoretical predictions by experiments conducted at the University of Tokyo Tank. Based on the results of the wave profile measurement of a supertanker model with bulbous bow, mentioned above, the phase relationship of the bulb wave (free wave pattern) to the hull wave was clarified, and these results immediately suggested a possibility of realizing a "Wave-Making-Resistanceless Hull Form" which has long been a dream of ship hydrodynamicists. The third paper is A STUDY ON THE WAVELESS STERN. Unlike the bow wave, the stern wave is affected by the boundary layer, growing thicker and unstable near the stern. In the design of bulbs, the starting point and amplitude function of the stern wave system must be known, however, only poor information about the behaviour of the stern wave is available. This was determined experimentally. As the first step, it is desirable that the bow wave system is cancelled and the stern wave system is sine term only, because the wave of the bulb also has sine term. Thus, by trail and error, the optimum bulb for the designed was obtained.
- Translated by H.C. Kim and edited by F.C. Michelsen.
University of Michigan, Ann ArborDepartment of Naval Architects and Marine Engineers
Ann Arbor, MI USA 48109
- Inui, T
- Takahei, T
- Kumano, M
- Publication Date: 1969-9
- Features: References;
- Pagination: 117 p.
- TRT Terms: Bows; Wave resistance; Waveform analysis
- Old TRIS Terms: Bulbous bows; Model testing
- Subject Areas: Design; Marine Transportation;
- Accession Number: 00084449
- Record Type: Publication
- Source Agency: University of Michigan, Ann Arbor
- Report/Paper Numbers: #032
- Files: TRIS
- Created Date: May 1 1975 12:00AM