 |
| Titel |
A wetting and drying algorithm for non-hydrostatic models with combined pressure/free-surface |
| VerfasserIn |
Simon Funke, Chris Pain, Stephan Kramer, Matthew Piggott |
| Konferenz |
EGU General Assembly 2011
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250046210
|
|
|
|
|
|
| Zusammenfassung |
| A wetting and drying algorithm for numerical modelling of three-dimensional free-surface
flows is proposed and analysed. In contrast to other wetting and drying methods it is
specifically designed for the non-hydrostatic Navier-Stokes equations. It makes use of
different boundary conditions applied to the surface boundary of the computational domain,
depending on whether it is considered to be wet or dry. This allows the use of a horizontally
fixed mesh and therefore expensive remeshing procedures are avoided. However, a simple
and cheap vertical mesh adaptation is performed to accurately represent free-surface
movements. Finally, a positive water level is ensured in dry regions by maintaining a thin
fluid layer. The spatial discretisation is done using the finite element method on a
non-uniform, unstructured mesh and an implicit timestepping is applied for the
temporal discretisation. The latter allows large timesteps and in particular there
is no constraint of how many mesh elements can be dried or wetted in a single
timestep.
The resulting scheme is implemented and tested in the Imperial College Ocean Model
[Piggott et al, 2008], a fully unstructured, non-hydrostatic ocean model and proved to be
stable and accurate on a wide range of testcases. These features are illustrated on a
demanding test in an idealized domain with known analytical solution. In addition, a
tsunami run-up simulation onto a complex three-dimensional beach is presented. Its
input data is based on laboratory experimental data of the Hokkaido-Nansei-Oki
tsunami that struck Okushiri Island, Japan, in 1993 with an run-up height of up to 30
m.
References
M.D. Piggott, G.J. Gorman, C.C Pain, P.A. Allison, A.S. Candy, B.T. Martin and W.R. Wells,
“A new computational framework for multi-scale ocean modelling based on adapting
unstructured meshes”, International Journal for Numerical Methods in Fluids, vol. 56, pp.
1003-1015, 2008 |
|
|
|
|
|
|