English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The classical Richards equation of water infiltration in unsaturated soil is a partial differential equation, which is non-linear and difficult to solve analytically. Taking time as the variable with the least action, the infiltration path as a function of time is established based on the Richards equation. The vertical infiltration problem of unsaturated soil under gravity is transformed into the functional extremum problem, and solved with the Euler-Lagrange equation. The results show that the diffusion coefficient  D ( θ ) has a functional relationship with the depth of the wetting front. When the type of diffusion coefficient is known, the moisture content of the wetting front at a specified depth, the moisture content of the farthest wetting front and the maximum entropy distribution of soil moisture content can be obtained at the optimal path. Taking the optimal path as the standard, the accuracy of solving the Richards equation by Boltzmann transformation and linear transformation is tested.

hydrological sciences journal

Study of the water vertical infiltration path in unsaturated soil based on a variational method: application of power function distribution of  D ( θ )