A method of analyzing unsteady, unsaturated flow in soils

Abstract

A numerical method of analyzing unsteady, unsaturated flow in soils is presented. If the hydraulic and capillary characteristics of the soil and the initial moisture condition are known, the method permits prediction of the future disposition of soil moisture as a function of time and location. The technique is particularly adaptable to problems of infiltration, drainage, and upward flow induced by evaporation. Effects of hysteresis and vapor movement are neglected. Darcy's law is combined with the continuity principle, and a solution is achieved through a step‐by‐step numerical procedure. Soil moisture profiles are obtained from a digital computer. Though at the present stage of development the method is applicable only to idealized soils, it is anticipated that further research will permit its application to field conditions.

Prediction of numerical homogenization using deep learning for the Richards equation

“…In general soils, unsaturated flow occurs when water seeps through many soil pores, evaporation dries up the topsoil, or water moves downward [48,62]. This typically results in the idea of soil moisture [62], which is defined by water potential (the energy state of water) and water content (the volume of water held in the spaces between unsaturated soil particles for any given soil sample). Soil moisture is essential for several hydrological, ecological, and biogeochemical procedures, even though it is not a major part of the water cycle.…”

“…depend heavily on soil moisture. Richards equation [53,6,5,35,26] describes mathematically the related processes, showing how water flows through unsaturated soil surface that is filled with both air and water [18,62].…”

Determination of deep percolation losses in loessial soils

“…TVo rather unique analyses of the unsaturated flow problem have appeared in the literature recently. Wang (1963) and Wang et al (1964) used a concept of moving sections having a fixed moisture content which varied in size with time to estimate moisture flow during infiltration in uniform soils. In another study, an electric analog was developed to approximate the nonsteady state, one dimensional solution of several moisture, temperature, and air pressure problems in soil (Hanks and Bowers, 1960).…”

Determination of deep percolation losses in loessial soils

“…Wang (1963) and Wang et al (1964) used a concept of moving sections having a fixed moisture content which varied in size with time to estimate moisture flow during infiltration in uniform soils. In another study, an electric analog was developed to approximate the nonsteady state, one dimensional solution of several moisture, temperature, and air pressure problems in soil (Hanks and Bowers, 1960 Classical experiments on the downward entry of water into air dry soils were performed ty Bodman and Coleman (1943) and Coleman and Bodman(1944).…”