This study began in 2007 when the tanker oil spill occurred on the west coast during a disaster recovery site. The destruction of the marine environment is perceived as a cause of neglect of safe operation but a safety insensitivity of our society. It takes a lot of time and money to recover from accident damage.
Korea's coastal areas have many sensitive seas with high value for use such as aquaculture farms. Oil tankers loaded with oil in this area are operated infrequently.
There are many obsolete and corroded oil facilities in the island and land. It also has geopolitically diverse weather characteristics.
In order to prevent soil pollution on land, the prevent brace of oil storage capacity are installed in consideration of the worst situation. However, Oil fences are the best way to control oil pollution at sea. This is insufficient to prepare for the worst situation such as bad weather.
Oil fence has structural loss such as entertrainment failure and drainage failure depending on weather conditions. There are also cases where the contaminants are lost to the bottom of the oil fence to attract and remove the contaminants into the safe areas.
Prior experiments confirmed the loss of function of the oil fence. As a result of experiment, it was recognized that it is important for the rear bulkhead among double walls.
In this study, the slope of the rear bulkheads were set to 10°, 20°, 30°, and 45° to study the flow characteristics around the bulkheads according to the oil fence skirt slope for marine pollution prevention. PIV measurements and CFD numerical analyzes were performed to quantify the flow characteristics around the bulkheads.
The oil fence used in the experiment was Class C type and the accumulation ratio is 1 : 6. Double bulkhead modeling is shown in Fig. 3.4. The u-velocity was applied to the Reynolds number considering the flow rate in the Incheon sea area.
As a result of analyzing the flow characteristics in a single bulkhead up to 20° a stagnant region was formed on the front top of the bulkhead. On the other hand, more than 30° flow separation the bottom of the bulkhead to occur.
There is a forced vortex circulation between the bulkheads and the largest stable shape at the slope of 20°. Therefore, it is estimated that oil fences designed and operated in double wall shape will be effective for towing contaminants to safety zones or collecting them.
At the inclination slope of 20° and the flow rate of 1.6 knots, there were two rising current points between the bulkheads. On the other hand, there was no updraft point at 1.9 knots.
If the inclination slope is more than 30°, the secondary vortex generated around the rear bulkhead rotates in the opposite direction to the upward flow of the internal circulation and is a factor that affects the outflow of the internal fluid.
In order to prevent secondary damage from marine pollution, it is necessary to know the meteorological characteristics of each sea area and improve the performance of the oil fence.
It is expected that the results from the paper will be used as basic data for the design of the shape of the oil fence and applied in the actual field. In addition, it is necessary to expand the control equipment that can prevent the spread of pollution in the early and feedforward control that effectively arranges and operates the control equipment in consideration of the meteorological characteristics of each sea area.