Abstract
This paper describes a new simulation technique for diffusion phenomena over the sea surface using Cellular Automata (CA), which is capable of making prediction of oil dispersion from tankers come into collision or stranded on rocks. Automaton is known as an abstract expression of sequencial machine in the field of information science, and CA is recognized as one of the model of finite state automata with sectional analysis domain called “cell”. CA has also been applied to demonstrate various engineering phenomena, and one of the most promising application field is flow simulation of viscous fluid, percoration, multi-phase fluid, reaction diffusion problems and so on. In this field, CA is called Lattice Gas Automata (LGA) and the solutions by LGA has been proved to coinside those by Navier-Stokes equation. In the procedure of CA, the analytical area is devided into cells and all the state variables defined on each cell are made transition by local neighbor rule and transition rule along the discrete time steps without solving the governing equation.
In the present paper, CA is applied to solve a diffusion problem in which the simulation results are compared to the analytical solution of diffusion equation, and possibility is shown in predicting the oil dispersion in the accident of tanker occured in Japan Sea in January, 1997, as an example. It is shown that the simulation by CA shows good agreement with the analytical solution of diffusion equation, and that the prediction of oil dispersion in Japan Sea can be made in a short time by a personal computer.
