HR: 16:00h
AN: H44A-01    [Abstracts]
TI: The Effect of Bottom Curvature on Mudflow Dynamics: Theory and Experiments
AU: * siviglia, a
EM: nunzio@diam.unige.it
AF: Dipartimento di Ingegneria Ambientale Universita di Genova, via Montallegro 1, Genova, 16145 Italy
AU: cantelli, a
EM: cante004@umn.edu
AF: St. Anthony Falls Laboratory, 3rd Ave. @ Mississippi River, Minneapolis,, MN 55414 United States
AB: A one-dimensional mathematical model of mudflow dynamics is formulated assuming mud to behave rheologically as a Herschel-Bulkley fluid. Novel features of the present contribution regard the propagation of mud-flows over a curvilinear bottom. A set of nonlinear partial differential equations is found to govern the unsteady, non-uniform flow of such fluids. Following the approach of {\it Huang and Garc{\`{\i}}a} [1998], depth-integrated forms of the continuity equation, as well as shear-integrated and plug-integrated forms of the momentum equations are derived. A perturbation analysis is also carried out under the assumption of 'slender' flow. The leading order problem takes the form of a kinematic wave equation. A free oscillating numerical solution of this hyperbolic conservative equation is obtained using the flux corrected transport (FCT) method. Characteristics and run out distances of the mud-flow are studied. The effects of bottom curvature on mud-flow dynamics is analyzed. Experiments are performed releasing a given volume of Kaoline and water mixture from a reservoir into an upward concave wide channel. Comparison between the numerical solution and the experimental data are generally satisfactory, though suggesting limitations typical of any approach which neglect convective accelerations.
DE: 3210 Modeling
DE: 1815 Erosion and sedimentation
DE: 1824 Geomorphology (1625)
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting