粗面と溶接ビードによる船の抵抗増加

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概要

• 論文の詳細を見る

• In order to estimate the resistance increase of ships due to the hull surface roughness, the drag and the velocity profile were measured on a smooth surface, sand surfaces, painted surfaces and welding bead models similar to those on hull surfaces. A 3,330mm long cylindrical body with a 500mm long floating test section was used for the measurements in a cavitation tunnel. The frictional resistance of the tested surface stuck on the test section was obtained by calibrating the measured drag using the Clauser plot of the velocity profile on the tested surface. The resistance increase due to the welding bead model was obtained from the difference between the measured drag with and without the welding bead model. The following results were obtained from the present experiments. (1) The roughness function of the sand surface agrees well with available data obtained from the conventional pipe flow experiments. (2) The roughness function of the painted surface is well expressed by using roughness shape parameter as ΔU/u^*=0.018√<λ/k_<MAA>>・k_<MAA>u^*/ν, where λ and k_<MAA> are the mean wave length and mean apparent amplitude of the surface roughness. (3) The drag coefficient of a welding bead model defined by the velocity at the bead height in the boundary layer is approximated as C'_<DW>=0.33+0.45h/b, where h/b is the height to breadth ratio of the welding bead model. (4) The resistance increase of a large ship due to the paint surface, estimated from the present experiments, is about 6〜9% of the frictional resistance of a equivalent flat plate, and that due to the welding beads is about 1〜3%.

• 社団法人日本船舶海洋工学会の論文
• 1988-03-22

著者

• 白勢 康

  IHI

• 白勢 康

  石川島播磨重工業(株)技術研究所

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• 粗面と溶接ビードによる船の抵抗増加

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