Abstract: Darcy`s law for laminar flow of fluids in porous media is an essential assumption in determining permeability, magnitude and direction of seepage force and travel time of fluid in porous media. Sand samples of different porosities from riverbed were used as porous media, a modelled experiment was set up to determine the volume of water flowing across a unit cross sectional area per unit time in these saturated sand samples packed in a vertical transparent cylindrical tube of radius 1.85×10-2m. Values of volume flux rate were determined for hydraulic gradient between 1.875 and 30.000 by using vertical flow form of Darcy’s equation. Darcy’s law is not perfectly obeyed by all samples used because both volume flux and seepage velocity increase as smaller rate than hydraulic gradient. The extent of deviation from Darcy’s law increases with decreasing porosity. The velocity is zero in sand samples A-E for gradient ranges of 0.029< i < 0.758. A plot of deviation from Darcy’s law against porosity shows that deviation is related to porosity, with polynomial fitting of degree 2 with correlation coefficient of 0.99.
O.I. Popoola , J.A. Adegoke and O.O Alabi , 2007. A Laboratory Study of the Effects of Porosity on the Deviation from Darcy`s Law in Saturated Porous Media. Research Journal of Applied Sciences, 2: 892-899.