Abstract
In the previous reports, the authors proporsed an equipment enclosing a hull with curtains for the prevention of spilt oil diffusion. At the decision of dimensions of the curtains, it is important to know the behavior of enclosed oil by the curtains and the performance of the equipment. In this paper, a two-dimensional hull model and rigid curtains are fixed in a circular tank and some experiments that heavy oil is spilt from the hull are carried out for various quantity of oil and velocities of flowing water. The experiments show that the equipment can prevent spilt oil diffusion and that internal waves are caused at the interface of the water and oil enclosed by the curtains. Non-dimensional wave height, H_<od>/χ_<od>, has a close relation with Froude number, Fc, where, H_<od> : height of internal waves, χ_<od> : horizontal distance between broadside and a curtain at the interface of the water and oil, Fc=ρν^2_b/Δρg√<S_<wd>>, here, ρ : density of oil, Δρ : density difference of oil and water, ν_b : velocity of flowing water under the bottom, g : acceleration of gravity force, S_<wd> : an area of vertical section of the region enclosed by the broadside and a curtain under the oil layer. Furthermore, it is clarified that oil droplets are generated at the crest of the waves when Fe is more than 0.26.
