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Abstract


This study firstly conducts the numerical simulates of tidal flow and the Japan Current and the wind drift flow.
The calculation result shows that the wind-driven flow is prevalent in this region. With the flow simulated, the study simulates the spreading of oil to the Japanese Coast using the Lagrangean analysis of surface particle motion.
The results of the numerical simulation are compared with the field investigation of the oil dispersion and the contamination ashore.
The condition of oil contamimation along the coastline has been investigated in the field for a wide region affected. The form of the rewashied oil is ball-like, with the big smudhe found at places.

The Japan Sea receives a very strong seasonal wind in winter and the frequences of wind direction and wind force are analyzed for this period from the weather chart. The result was used to the wind-driven flow simulation.

The numerical model for the tidal flow, the Japan Current and wind driven flow in the Japan Sea is conducted by integrating the depth- averaged two-dimensional equations with the ADI scheme. The grid system with spacing of 15km for the region of 613kmW-E, and 465kmS-N. And the procedure to reproduce the field data of the tidal flow, the Japan Current and the wind drift flow is described. Next, numerical floats are placed at the sunk point of the bow part and the ship-body part evenly at the beginning and their loci are traced with the given data of the flow and the turbulent component representing the turbulent diffusion.

The former information, i.e. the flow, possibly gives the prediction of the overall ability of flushing contaminant out of this area and the latter, i.e. diffusion, local distribution of the oil mass. To calculate float dispersion, the locus of an individual float is traced to produce dispersion of a number of floats.

The numerical simulation of oil driven ashore shoewd a good agreeement with the field data.



GLESCO
( GLobe, EStuary and COast )
Hydraulic Engineering Lab. Nagaoka University of Technology