Validation of the Cooray‐Rubinstein (C‐R) formula for a rough ground surface by using three‐dimensional (3‐D) FDTD
Validation of the Cooray‐Rubinstein (C‐R) formula for a rough ground surface by using three‐dimensional (3‐D) FDTD
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DOI：
10.1002/2013jd020078
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发表时间：
2013-11
期刊：
影响因子：
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通讯作者：
Dongshu Li;Qilin Zhang;Tao Liu;Zhenhui Wang
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文献类型：
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作者：
Dongshu Li;Qilin Zhang;Tao Liu;Zhenhui Wang
本文将Cooray-Rubinstein(C-R)近似公式推广到分形粗糙地表，并在距闪电通道50m和100m处用三维(3-D)时域有限差分(FDTD)方法验证其精度。结果表明，扩展的C-R公式对分形粗糙导电地面上方雷电辐射水平电场的预测具有一定的精度，且随着大地电导率的增大，其精度略有提高。例如，当粗糙地面的电导率为0.1 S/m时，扩展的C-R公式预测的峰值误差不超过2.3%，而当电导率为0.01 S/m时，其误差不到6.7%。粗糙地面对雷电水平场的影响很大，在早期(回击开始几微秒内)，水平电场的初始峰值随粗糙地面均方根高度的增加而明显减小。
In this paper, we have extended the Cooray‐Rubinstein (C‐R) approximate formula into the fractal rough ground surface and then validate its accuracy by using three‐dimensional (3‐D) finite‐difference time‐domain (FDTD) method at distances of 50 m and 100 m from the lightning channel. The results show that the extended C‐R formula has an accepted accuracy for predicting the lightning‐radiated horizontal electric field above the fractal rough and conducting ground, and its accuracy increases a little better with the higher of the earth conductivity. For instance, when the conductivity of the rough ground is 0.1 S/m, the error of the peak value predicted by the extended C‐R formula is less than about 2.3%, while its error is less than about 6.7% for the conductivity of 0.01 S/m. The rough ground has much effect on the lightning horizontal field, and the initial peak value of the horizontal field obviously decreases with the increase of the root‐mean‐square height of the rough ground at early times (within several microseconds of the beginning of return stroke).