流出油拡散防止膜の滞油限界と膜諸元に関する一考察

Abstract

The authors proposed "Oil-curtain" which prevents spilt oil from diffusion by enclosing a hull with thin curtains just after a tanker accident. In the design of the device, external conditions which influence the performance to contain oil should be given. In this paper, the conditions are investigated and some model experiments are carried out to examine the performance under the conditions. In addition, the fundamental guidance required in fixing the principal factors of the device, depth of the curtain and weight of the sinker, is shown. The obtained results are summarized as follows. (1) A percentage of oil spillage against carrying capacity depends on dead weight tonnage of a ship. Therefore, the capacity to contain oil should be estimated at every tonnage. (2) 4 knots is the maximum flowing velocity to contain oil by the curtain with the sinker of 1kg/m^2 against Acw, where, Acw=an area of the curtain in water. (3) In beam sea, the contained oil is thrown up onto the deck by waves of less than 3m height. (4) The shape of curtain containing oil can be replaced to the simple model which is calculated with two dimensional analysis. The calculated Ym is larger than experimental results, where Ym=transverse distance between ship's side and the curtain expanded by hydrostatic pressure of oil. (5) To contain oil effectively in flow or beam sea, the additional depth of curtain under the oil layer is from 0.2Ym to 1.5d, where d=ship draft.