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Titel |
Exact solutions of ideal dam break flood for arbitrary cross-section |
VerfasserIn |
H. B. Ma, J. Heyman, C. Ancey, X. D. Fu |
Konferenz |
EGU General Assembly 2012
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Medientyp |
Artikel
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Sprache |
Englisch
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 14 (2012) |
Datensatznummer |
250065100
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Zusammenfassung |
Abstract: Even though it oversimplifies reality, the dam-break problem for frictionless fluids
provides predictions relevant to various manmade and natural dam-break floods. The exact
solution can also be used to test numerical schemes. However, as far as we are aware, exact
solutions derived from the nonlinear shallow-water equations hold only for infinitely wide
cross-sections, a feature that contrasts with most natural streams. In this study, we start from
the nonlinear shallow-water equations for arbitrary cross-section and model the ideal
dam-break flood resulting from the sudden release of an inviscid, incompressible fluid on
frictionless bed. Two cases are considered downstream of the wave front: the wet and dry
bed. For both cases, irregular cross-section entails changes in the expression of the
Riemann variables. For wet beds, an implicit solution is worked out using the Riemann
method, which makes it possible to find approximate solutions (to any order). For dry
beds, a closed-form solution can be derived. The solutions show that for the same
initial conditions, the flood wave features depend a great deal on the cross section.
The talk is illustrated with various examples, which show that the assumption of
infinitely wide cross section should be used carefully when modeling real dam break
floods.
Keywords: Dam break, Arbitrary cross-section, Riemann solver, Exact solution. |
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