Glass Bead Porous Media Research Articles

Water movement in glass bead porous media: 2. Experiments of infiltration and finger flow

This paper presents experimental observations of infiltration and finger flow in glass beads. In paper 1 (Lu et al., this issue), we showed that the total surface tensile force is much greater in initially wet profiles than in initially dry profiles. During capillary rise in glass beads, the “jump” process takes place for an initially dry condition, whereas in an initially wet profile not only a jump process but a film thickening associated with film flow characterizes capillary rise. In this paper, infiltration experiments into initially dry glass beads show that the wetting front is relatively saturated and flat compared with the unsaturated and irregular wetting front into an initially wet profile. In the experiments of finger flow, photographs show that the tip of the finger is completely water saturated and that no partially saturated zones exist around the saturated tip. The fingers initiated in a dry zone disappear when they reach an initially wet lower zone even when the packing conditions of the glass beads are identical. Hence the criterion for instability when water is applied at a rate less than the value of the saturated hydraulic conductivity does not apply to an initially wet condition. When a fine layer of glass beads lies on a coarse layer that is initially dry, fingering will take place during infiltration and flow is unstable. If the coarse lower layer is initially wet, finger flow does not develop, and the flow remains stable. More investigations are required to ascertain threshold values of the initial water content causing instability of water movement in porous media.

Limitations of Darcy's Law in Glass Bead Porous Media

Soil Science Society of America JournalVolume 37, Issue 2 p. NP-NP ErratumFree Access Limitations of Darcy's Law in Glass Bead Porous Media This article corrects the following: Limitations of Darcy's Law in Glass Bead Porous Media L. Boersma, F. T. Lindstrom, S. K. Saxena, Volume 37Issue 2Soil Science Society of America Journal pages: 333-335 First Published online: March 1, 1973 L. Boersma, L. BoersmaSearch for more papers by this authorF. T. Lindstrom, F. T. LindstromSearch for more papers by this authorS. K. Saxena, S. K. SaxenaSearch for more papers by this author L. Boersma, L. BoersmaSearch for more papers by this authorF. T. Lindstrom, F. T. LindstromSearch for more papers by this authorS. K. Saxena, S. K. SaxenaSearch for more papers by this author First published: 01 March 1973 https://doi.org/10.2136/sssaj1973.03615995003700020054xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume37, Issue2March-April 1973Pages NP-NP RelatedInformation

Limitations of Darcy's Law in Glass Bead Porous Media

AbstractIn a series of dispersion experiments in porous systems made up of glass beads, it was found that for flow of water through small pores at low gradients, flow rates are not proportional to the hydraulic gradient but are proportional to this gradient raised to the power 1/n, where n > 1. These results agree with literature reports which have indicated that for flow through small pores, the flow fields undergo a change from Newtonian to non‐Newtonian behavior. The deviations have been attributed to force fields associated with the clay minerals, changes in the clay fabric making up the porous system, and electro‐viscous effects. In these experiments, the porous systems were made up of glass beads so that all effects attributed to clay‐water interactions could be ruled out. The functional relationship between the factor 1/n and pore radius r was found to be approximated by 1/n = 1 − exp(−1.32r0.31).