Hydraulic behaviour of parallel fibres under longitudinal flow: a numerical treatment
Modelling fluid flow through fibrous porous materials has gained increasing attention from industry and research communities. Analytical and numerical methods are commonly used to predict the hydraulic characteristics of fibrous material during fluid flow, although to date most techniques have been conducted using the same assumption that the geometric features of fibres remain unchanged. In other words, the mutual interaction between fibre elements and fluid is ignored, which undermines the actual working condition of fibres. This paper therefore presents a potential numerical approach that is capable of capturing the behaviour of a fluid-solid system. Individual fibres are simulated by the discrete element method (DEM) coupled with the concept of computational fluid dynamics (CFD), whereby the information contained in each phase is constantly exchanged and updated with other phases. In comparison with conventional solutions, including the Kozeny-Carman (K-C) fluid flow principle and other valid studies, the results show an acceptable agreement in predicting the hydraulic conductivity of a fibrous system. Subjected to laminar longitudinal flow, fibre motion is also evaluated with respect to varying bond stiffness and flow velocity. The study indicates the potential of the proposed technique in modelling drainage and filtration that is based on the hydraulic behaviour of fibrous porous geomaterials.