Properties of Channel Extension and Expansion of Upward Positive Connecting Leader from Tall Tower
| Autor: | Zilong Qin, Ya-ping Du, Zongxu Qiu, Yan Gao, Mingli Chen |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Physics
010504 meteorology & atmospheric sciences 020209 energy Geometry 02 engineering and technology Extension (predicate logic) Radius 01 natural sciences Tower (mathematics) Lightning Corona (optical phenomenon) Electric field 0202 electrical engineering electronic engineering information engineering 0105 earth and related environmental sciences Communication channel Arithmetic mean |
| Zdroj: | 2018 34th International Conference on Lightning Protection (ICLP). |
| Popis: | We have analyzed the properties of channel extension and expansion of one upward positive connecting leader (UPCL) in a lightning struck to the 356 m high Shenzhen Meteorological Gradient Tower (SZMGT) based high-speed camera images. The UPCL behaved obvious stepwise when it extended upward, with a mean step length of 2.6 m, a mean inter-step interval of 27 μ s, and a mean average speed of $1.06 \times 10^{5}$ m/s. The luminous channel radius of the UPCL as a function of time had a stable increasing trend before the return stroke, but showed a periodical shrinking and expansion property after the return stroke, with an average channel expansion speed of $\sim 10^{4} m/s$. More importantly, the luminous channel radius had an obvious increasing trend with the increase of height, which was about 2.5 m (minimum) $\sim$ 4.5 m(maximum) when around the tower tip and about 3.6 m (minimum) $\sim 6.6$ m(maximum) when at 24 m high above the tower tip. Such a channel radius property is well in consistent with the modeling results of the leader corona sheath radius in literature. |
| Databáze: | OpenAIRE |
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