Study of non-linear flow in coarse granular material through converging boundaries

Abstract

Over the past century, there has been a continuously growing research interest in fluid seepage through coarse porous material. Experimental data on nonlinear flow behaviour in several coarse granular materials are provided in the current work. The aim of the present work is to investigate, theoretically and experimentally, the seepage patterns arising from non– Darcy fluid flows through coarse granular materials, with a particular reference to the effect of convergence. Along with the above, the effect of variation in size and shape of the media on the seepage patterns is also analyzed. Experiments have been conducted on flow through porous material with converging permeameter and equations relating the different parameters affecting the seepage flow are established. A thorough review of different regimes of seepage flow has been carried out. In order to meet the prime objective, i.e., to propose governing equations for different regimes of radial seepage flow, experiments are conducted in a converging permeameter with crushed rock and small glass balls as solid material and water as fluid media. The analysis of the experimental data is carried out in two phases. In first phase, coefficient of resistance and Reynolds number is computed using ‘volume diameter’ as ‘characteristic length’. Then expressions relating these two parameters are proposed for different regimes of flow. In second phase, hydraulic radius is used as characteristic length while defining the coefficient of resistance and Reynolds number. Then analysis is repeated as done in first phase and the corresponding equations have been proposed relating the coefficient of resistance and Reynolds number.