Sun Hongguang, Meerschaert Mark M, Zhang Yong, Zhu Jianting, Chen Wen
College of Hydrology and Water Resources, Hohai University, Nanjing 210098, China.
Adv Water Resour. 2013 Feb 1;52:292-295. doi: 10.1016/j.advwatres.2012.11.005.
The traditional Richards' equation implies that the wetting front in unsaturated soil follows Boltzmann scaling, with travel distance growing as the square root of time. This study proposes a fractal Richards' equation (FRE), replacing the integer-order time derivative of water content by a fractal derivative, using a power law ruler in time. FRE solutions exhibit anomalous non-Boltzmann scaling, attributed to the fractal nature of heterogeneous media. Several applications are presented, fitting the FRE to water content curves from previous literature.
传统的理查兹方程表明,非饱和土壤中的湿润锋遵循玻尔兹曼标度律,运移距离随时间的平方根增长。本研究提出了一个分形理查兹方程(FRE),用分形导数代替含水量的整数阶时间导数,采用时间上的幂律尺度。FRE解表现出异常的非玻尔兹曼标度,这归因于非均质介质的分形性质。给出了几个应用实例,将FRE拟合到先前文献中的含水量曲线。