Fundamentals of mathematical modeling of moisture transfer in the soil

"Fundamentals of mathematical modeling of moisture transfer in the soil", organizado por CITMAga. Será impartido por Nazerke Rysbayeva (Kazakh-British Technical University).

Data: 18 de xullo de 2024.

Hora: 10:00 h.

Duración: 1 hora

Lugar: Aula Magna da Facultade de Matemáticas (USC) e online por MS Teams a través do enlace Teams Meeting.

Abstract:

Mathematical modelling of many natural processes and phenomena is based on the concept of continuous medium. The term “continuous medium” does not mean that there are no pores or cracks that contain moisture, gas or mixture of fine particles. Solid phase of continuous medium can be nonporous (faintly porous), porous or capillary.

At the present time, methods of mathematical modelling of moisture transfer are widely spread abroad. It has been noted that experimental methods and approaches need to be improved. Moisture transfer in saturated soil can be written by using Darcy’s. In this case, the moisture transfer velocity is proportional to the pressure gradient

where 𝐾𝐾(𝜕𝜕) – moisture conductivity coefficient that depends on coordinates 𝑥𝑥, 𝑦𝑦, 𝑧𝑧; 𝜕𝜕 – volumetric humidity of soil; 𝐻𝐻 – pressure; t – time. Humidity of soil can vary depending on the movement. If at the initial time the soil has an uneven distribution of moisture along the depth, then with time the moisture will increase in drier layers according to the diffusion law. This phenomenon is called the Aller effect, which uses the concept of fractured porous soil to describe the noted fact. A correction term is included into the moisture transfer equation, which takes into account moisture transfer in soils. Hence Aller's model has the following form:

where 𝐴𝐴, 𝐷𝐷 – proportionality coefficients.