COMPUTATIONAL METHOD FOR FREE-SURFACE FLOWS BETWEEN MULTIPLE ABSORBENT PARTICLES

Abstract

A computational method was proposed for the free-surface flows intruding between multiple absorbent particles on the basis of the finite volume method. In the proposed method, the solid area of the particle, which is in contact with water, expands due to the swelling of the absorbent particle. The influences of particle swelling and water absorption on flows are considered with velocity and pressure boundary conditions on the particle surfaces. The proposed method was first applied to the lock-exchange problem in porous media, which consist of multiple non-absorbent particles. Second, the swelling of a single absorbent particle was calculated with the present method in saturated and unsaturated conditions. The basic applicability of the proposed method was confirmed through the discussions about the front position of the heavy current in the first calculations as well as the volume conservation of water in the second investigations. In addition,the proposed method was applied to the dam-break flows in the porous media, which consist of multiple absorbent particles. As a result of the numerical experiments, it was demonstrated that the flow patterns intruding the porous media are largely affected by the swelling particles. In particular, it was found there is a possibility that the total amount of water absorption decreases due to the blocking of the flows by the swelling particles even in case the water absorption speed of the particles is sufficiently high.