オイルフェンスの性能(滞油能)に関する実験

Abstract

At the treatment of spilled oil on sea mechanical barriers (boom, oilfence) are feasible in mild sea weather conditions but there are many unknown factors on uses and controls of them corresponding to the various behaviors and configurations of the oil layers which are kept at the front of them. The states of the oil layers kept by the barriers are studied by using a waterway of 30cm width, 20cm height and 140cm length, in which the water stream is uniform at volantary speed below 25cm/sec. Results found by experiments are as follows ; (1) The states of the oil layers are divided roughly into three zones. (2) The relations between the states of the oil-water bordering surface of each zone and the effects of the water current upon it are explained as follows ; (a) The headwave at the front part of the oil layers are caused by the water current pushing the leading edge of the oil layers near the water surface. (b) The travelling waves at the middle zone of the oil layers are caused by the water current contacting the oil layers. (c) The standing waves near the skirt of the barriers are caused by returning water and eddy current. The behaviors of the oil layers due to the water current are very complicated according to the encounting influence of the headwave and the travelling waves, there often generates the oil droplet at the crest of a large wave. Thus the states of staying oil layers are classified into two situations as follows ; (1) A stable situation ; The frequency and the amounts of oil leakage under the skirt are very rare and little respectively. (2) An unstable situation ; The frequencyy and the amounts of oil leakage are often and large respecively. (3) Oil-keeping capacity of the barriers are estimated by the product of the oil-amount (Q) kept by the barriers and the speed (v) of the water currents.