1990 Fiscal Year Final Research Report Summary
Three Dimensional Numerical Simulation of Stepped Leadee by means of Fractal Model
| Project/Area Number |
01550220
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
電力工学
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| Research Institution | Osaka University |
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Principal Investigator |
KAWASAKI Zen-ichiro Fac. Engineering Dept. Electrical Engineering, 工学部, 講師 (60126852)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Fractal / Stepped leader / Lightning / Simulation / Space charge / Winter Thunderstorm |
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| Research Abstract |
Three-dimensional numerical simulations of a stepped leader near the ground surface are carried out by using the Leader Progression Model which is improved by using the novel mathematical concept, Fractal. The finite difference method is applied to the three dimensional Poisson's equation and the stepped leaders, which are initiated at the lower part of the cloud and usually are proceeding toward the artificial constructions on the ground, are simulated to study the theoretical stepped leader progression. The zig-zags and branches of channels, which are believed to be the representative characters of lightning channel, can be simulated in this study.
Besides the numerical simulations, lightning channel's features are examined by estimating the Fractal dimensions of lightning channels of still pictures. The average estimated Fractal dimensions is about 1.2, and the estimated Fractal dimension is used to evaluate the numerically simulated results. Through this study the Fractal stepped leader model is completely established.
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