Effect of convergent boundaries on post laminar flow through porous media

Effect of convergent boundary over the post laminar flow through porous media is experimentally investigated in the present study. Laboratory experimentations are performed in specially designed radial flow permeameters with 45, 60 and 75 convergent angles with crushed stones and glass spheres used as porous medium. Tap water and a mixture of water with 10% glycerine (by weight) are used as the fluid medium. Obtained Results are compared with published data from a parallel flow permeameter and it is observed that the parallel boundary offers greater resistance to the flow than convergent boundaries. Furthermore, effect of convergent boundaries over the coefficients of binomial equation (Forchheimer equation) and power law (Wilkins equation) is studied. Based on the observation of ambiguous variation pattern of Forchheimer coefficients and a well defined variation trend of the Wilkins coefficients with the change in radial angle; the Wilkins equation can be stated to be better suited for modelling of the velocity, hydraulic gradient relationship in the post laminar flow through convergent boundaries. Such modelling can aid in understanding and designing of hydraulic structures associated with the post laminar flow through radial boundaries such as areas adjacent to a pumping well, rock fill dam, water filters etc. (C) 2018 Elsevier B.V. All rights reserved.