source: anuga_work/production/dampier_2006/report/computational_setup.tex @ 3955

Last change on this file since 3955 was 3955, checked in by sexton, 17 years ago

(i) dampier report tex and figures (ii) export_results for parallel output

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1To set up a model for the tsunami scenario, a study area is first
2determined. Here, we define the study area to cover around km of coastline
3and extending offshore to around the 70m depth contour. Onshore data covers the
4area of interest to CIPMA. The study area is around 6250 km$^2$.
6The finite volume technique relies on the construction of a triangular mesh which covers the study region.
7This mesh can be altered to suit the needs of the scenario in question. The mesh can be refined in areas of
8interest, particularly in the coastal region where complex behaviour is likely to occur. For the purpose
9of this study for CIPMA, we will refine the mesh around the major onshore gas facility and the gas pipelines.
10In setting up the model, the user defines the area of the triangular cells in each region of interest\footnote{Note that the cell
11area will be the maximum cell area within the defined region and that each
12cell in the region does not necessarily have the same area.}.
13The cell areas should not be too small as this will cause unrealisticly long computational time,
14and not too great as this may inadequately capture important behaviour.
15%There are no gains in choosing the area to be less than the supporting data.
16Figure \ref{fig:dampier_area} shows the study area with regions of difference cell areas. The total number
17of cells is .
18Lateral accuracy refers to the distance at which we are confident in stating a region is inundated.
19Figure \ref{fig:dampier_area} shows the maximum triangular cell area and lateral accuracy for each region.
20Therefore we can only be confident in the calculated inundation extent surrounding the onshore
21gas infrastructure to within 30 m.
26  %\centerline{ \includegraphics[scale=0.15]{../report_figures/dampier_resolution_zones.jpg}}
28  \caption{Study area for Dampier scenario highlighting four regions of increased refinement.
29Region 1: Surrounds onshore gas infrastructure at Dampier with a cell area of 500 m$^2$ (lateral accuracy 30 m).
30Region 2: Surrounds the gas pipelines with a cell area of 5000 m$^2$ (lateral accuracy 100 m).
31Region 3: The remaining area is given a cell area of 100000 m$^2$ (lateral accuracy 450 m).
33  \label{fig:dampier_area}
37The final item to be addressed to complete the model setup is the
38definition of the boundary condition. As
39discussed in Section \ref{sec:methodology}, a Mw 9 event provides
40the tsunami source. The resultant tsunami wave is made up of a series
41of waves with different amplitudes which is affected by the energy
42and style of the event as well as the bathymetry whilst it travels
43from its source to Dampier. The amplitude and velocity of each of these
44waves are then provided to ANUGA as boundary conditions and propagated
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