Abstract
The authors have proposed a new device which encloses a hull with a curtain for preventing spilt oil diffusion. In this paper, the shapes of the curtain under steady flow are investigated on the basis of some model experiments. In the experiments, a few types of box shape hull models which are enclosed with a curtain are fixed in a circular tank and the shapes of the curtain are observed. The obtained results are summarized as follows. (1) An area of vertical section of "Region A", which is the region to contain spilt oil in the down-stream side, closely relates to a new non-dimensional number, F_s =<ρw> A_<cw> νw^2/Ws, where, ρw=water density, A_<cw>=An area of the curtain in the water, νw=flowing velocity, ws=weight of sinkers mounted on the foot of the curtain. (2) As Fs increases, the smooth outline of the curtain of the downstream side gets to break and a "furrow" is created back and forth. (3) The creation of the "furrow" mainly depends on Fs and Z_<bo> /L_<CR>, where, Z_<bo>=depth of the curtain under the ship's bottom, L_<CR>=length of the curtain round a ship. (4) To have sufficient ability of containing oil, the device should be designed so that the "furrow" is never created on the curtain.
