Modeling the movement of sediment slugs in a channel

Graduation Date

1998

Document Type

Thesis

Program

Other

Program

Thesis (M.S.)--Humboldt State University, Environmental Systems: Mathematical Modeling, 1998

Committee Chair Name

Roland H. Lamberson

Committee Chair Affiliation

HSU Faculty or Staff

Keywords

Humboldt State University -- Theses -- Mathematical Modeling, Sediment transport, Mathematical Modeling, Mathematical models

Abstract

The equations of continuity and momentum for the fluid, sediment continuity equation, Meyer-Peter and Müller sediment transport equation, and flow resistance equation are used to model the movement of a single wave of sediment, consisting only of bed material, introduced into a channel. The five equations are combined to form one equation relating sediment thickness to water flow variables and parameters. Two cases are considered; steady, critical water flow and unsteady, non-critical water flow. For steady, critical water flow, the combined equation becomes a diffusion equation that is solved both numerically and analytically to replicate experimental data provided by Lisle et al. (1997) and to determine sensitivity to the Meyer-Peter and Müller constant. Solutions compare well with the experimental data. For unsteady, non-critical water flow, the full St. Venant equations and the combined equation are solved simultaneously using the MacCormack explicit finite difference scheme. Using the unsteady non-critical flow model, twenty-seven numerical experiments are performed to model the effects of various parameters on the movement and degradation of the sediment slug. In general, increases in bed slope and water depth increase the rate of dispersion of the slug while increases in friction have the reverse effect. The rate of translation increases with increasing water depth and decreases with increasing friction. Increasing the bed slope not only increases the rate of translation, in some cases it changes the direction of translation.

https://scholarworks.calstate.edu/concern/theses/p5547t49q

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