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| Titel |
Simulating run-up on steep slopes with operational Boussinesq models; capabilities, spurious effects and instabilities |
| VerfasserIn |
F. Løvholt, P. Lynett, G. Pedersen |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1023-5809
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics ; 20, no. 3 ; Nr. 20, no. 3 (2013-06-13), S.379-395 |
| Datensatznummer |
250018975
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| Publikation (Nr.) |
 copernicus.org/npg-20-379-2013.pdf |
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| Zusammenfassung |
| Tsunamis induced by rock slides plunging into fjords constitute a severe
threat to local coastal communities. The rock slide impact may give rise to
highly non-linear waves in the near field, and because the wave lengths are
relatively short, frequency dispersion comes into play. Fjord systems are
rugged with steep slopes, and modeling non-linear dispersive waves in this
environment with simultaneous run-up is demanding. We have run an operational
Boussinesq-type TVD (total variation diminishing) model using different
run-up formulations. Two different tests are considered, inundation on steep
slopes and propagation in a trapezoidal channel. In addition, a set of
Lagrangian models serves as reference models. Demanding test cases with
solitary waves with amplitudes ranging from 0.1 to 0.5 were applied, and
slopes were ranging from 10 to 50°. Different run-up formulations
yielded clearly different accuracy and stability, and only some provided
similar accuracy as the reference models. The test cases revealed that the
model was prone to instabilities for large non-linearity and fine resolution.
Some of the instabilities were linked with false breaking during the first
positive inundation, which was not observed for the reference models. None of
the models were able to handle the bore forming during drawdown, however. The
instabilities are linked to short-crested undulations on the grid scale, and
appear on fine resolution during inundation. As a consequence, convergence
was not always obtained. It is reason to believe that the instability may be
a general problem for Boussinesq models in fjords. |
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