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| Titel |
Effective coastal boundary conditions for tsunami wave run-up over sloping bathymetry |
| VerfasserIn |
W. Kristina, O. Bokhove, E. Groesen |
| 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 ; 21, no. 5 ; Nr. 21, no. 5 (2014-09-23), S.987-1005 |
| Datensatznummer |
250120943
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| Publikation (Nr.) |
 copernicus.org/npg-21-987-2014.pdf |
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| Zusammenfassung |
| An effective boundary
condition (EBC) is introduced as a novel technique for predicting tsunami
wave run-up along the coast, and offshore wave reflections. Numerical
modeling of tsunami propagation in the coastal zone has been a daunting task,
since high accuracy is needed to capture aspects of wave propagation in the
shallower areas. For example, there are complicated interactions between
incoming and reflected waves due to the bathymetry and intrinsically
nonlinear phenomena of wave propagation. If a fixed wall boundary condition
is used at a certain shallow depth contour, the reflection properties can be
unrealistic. To alleviate this, we explore a so-called effective boundary
condition, developed here in one spatial dimension. From the deep ocean to a
seaward boundary, i.e., in the simulation area, we model wave propagation
numerically over real bathymetry using either the linear dispersive
variational Boussinesq or the shallow water equations. We measure the
incoming wave at this seaward boundary, and model the wave dynamics towards
the shoreline analytically, based on nonlinear shallow water theory over
bathymetry with a constant slope. We calculate the run-up heights at the
shore and the reflection caused by the slope. The reflected wave is then
influxed back into the simulation area using the EBC. The coupling between
the numerical and analytic dynamics in the two areas is handled using
variational principles, which leads to (approximate) conservation of the
overall energy in both areas. We verify our approach in a series of numerical
test cases of increasing complexity, including a case akin to tsunami
propagation to the coastline at Aceh, Sumatra, Indonesia. |
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