水流への混入空気の膨張による船体抵抗低減に関する研究

概要

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This paper proposes a principle of drag reduction on a ship hull which is accomplished by injecting air of atmospheric pressure into water flow. Expansion of the entrained air in water flow generates the high-speed two-phase water jet, and the drag reduction on the ship hull is caused by this reaction force ; therefore, the fluid drag can be reduced without the addition of an external energy. Three types of sailing bodies which have different spoilers were set in a towing tank, and the drag reductions were measured using various parameters such as sailing velocity, opening angle of the rear plate, and the depth of the sailing body in the water. The drag decreases monotonically with an increase of the sailing velocity and an increase of the opening angle of the rear plate. The sailing velocity at which the drag reduction begins converges toward higher speed as the depth of the sailing body increases. In order to examine the mechanism of the drag reduction analytically, a one-dimensional nonlinear lattice model is applied to the flow system. The proposed model is effective to investigate the flow characteristics.
社団法人日本機械学会の論文
1995-06-25