When a semi-infinite body of homogeneous fluid initially at rest
behind a vertical retaining wall is suddenly released by the removal
of the barrier the resulting flow over a horizontal or sloping bed
is referred to as a dam-break flow. When resistance to the flow is
neglected the exact solution, in the case of a stable horizontal bed
with or without `tail water', may be obtained on the basis of
shallow-water theory via the method of characteristics and the
results are well known. Discrepancies between these shallow-water
based solutions and experiments have been partially accounted for by
the introduction of flow resistance in the form of basal friction.
This added friction significantly modifies the wave speed and flow
profile near the head of the wave so that the simple exact solutions
no longer apply and various asymptotic or numerical approaches must
be implemented to solve these frictionally modified depth-averaged
shallow-water equations. When the bed is no longer stable so that
solid particles may be exchanged between the bed and the water
column the dynamics of the flow becomes highly complex as the
buoyancy forces vary in space and time according to the competing
rates of erosion and deposition. Furthermore, when the Froude
number of the flow is close to unity perturbations in the height and
velocity profiles grow into N-waves and the bed below develops
ripples which act to sustain the N-waves in the fluid above. It is
our intention here to study dam-break flows over erodible sloping
beds as agents of sediment transport taking into account basal
friction as well as the effects of particle concentrations on flow
dynamics including both erosion and deposition. We shall consider
shallow flows over initially dry beds and investigate the effects of
changes in the depositional and erosional models employed as well as
in the nature of the drag acting on the flow and the slope of the
bed. These models include effects hitherto neglected in such
studies and offer insights into the transport of sediment in the
worst case scenario of the complete and instantaneous collapse of a
dam. / Mathematics
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:AEU.10048/1527 |
| Date | 11 1900 |
| Creators | Emmett, Matthew |
| Contributors | Moodie, T. Bryant (Mathematical and Statistical Sciences), Swaters, Gordon (Mathematical and Statistical Sciences), Sutherland, Bruce (Physics), Bush, Andrew (Earth and Atmospheric Sciences), Flynn, Morric (Mechanical Engineering), Bush, John (Mathematics, MIT) |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 2251274 bytes, application/pdf |
| Relation | Emmett, Matthew (2008). Dam-break flows with resistance as agents of sediment transport. Physics of Fluids vol. 20 no. 8 pp. 086603., Emmett, Matthew (2009). Sediment transport via dam-break flows over sloping erodible beds. Studies in Applied Mathematics vol. 123 no. 3 pp. 257-290. |
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