Nonlinear Flow in Embankments

Ahmed, Nazeer; ,

Nonlinear Flow in Embankments

by Nazeer Ahmed, Univ of Nevada-Las Vegas, Las Vegas, United States,

Document Type: Proceeding Paper

Part of: Hydraulic Engineering

Abstract:

For a large number of water resources projects, the Dupuit-Forchheimer (D-F) assumption is considered a viable design criterion and, consequently, Darcy law is used to determine the locus of free surface for flow through a given porous medium. In contrast, the physical measurements of water level always provide the location of actual free-surface higher than that predicted by the analysis based on the D-F flow configuration. According to D-F assumption, conditions of linear flow are assumed to exist throughout the porous medium and the effects of convective and turbulent forces are ignored. This process introduces a permanent discrepancy into the flow phenomena that leads to approximate values of different hydraulic parameters. Besides, the analysis does mask the true character of the flow field yielding unrealistic design parameters. Therefore, it is obvious that the determination of true position of the free surface is crucial to the exact determination of the required hydraulic parameters. In this paper, the role of nonlinear flow in terms of convective and turbulent forces is included in the flow equation, as dictated by the Reynolds equations, to provide clear understanding of the flow phenomena and realistic answers to the problems of the project at hand.

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