View source for Mathematical Model TRIM-3D

[[Category:Mathematical Models]]
[[de: Mathematisches Verfahren TRIM-3D]]
==Short Description==
The mathematical [[model]] [[Trim|TRIM]]-3D is based on the finite difference method. In contrast to the two-dimensional (depth-averaged) mathematical [[model]] [[Mathematical Model TRIM-2D|TRIM-2D]], [[Trim|TRIM]]-3D is a fully three-dimensional [[model]]. [[Trim|TRIM]]-3D was designed to solve several transient nonlinear partial differential equations (pde's). The [[model]] is actually used to study one ore more of the following physical processes:

# transport of water (conservation of the water mass)
# transport of linear momentum (conservation of linear momentum)
# transport of salinity (conservation of the dissolved salt mass)

The [[model]] takes into account hydrodynamic pressure in the water body (non-[[hydrostatic pressure]] distribution). A simplifying hydrostatic approximation can be alternatively used. This approximation might be useful for natural systems with negligible vertical accelerations (compared with gravity).

[[Trim|TRIM]]-3D was developed by Prof. V. Casulli (Trento University, Italy). In the framework of a scientific cooperation [[Trim|TRIM]]-3D has been successfully installed in the year 1996 at BAW-DHs computers. It has been integrated into BAW-DHs numerical modelling toolbox and is now used on a routine basis in the context of different real-world projects concerning estuarine flow and transport processes. Meanwhile the code of [[Trim|TRIM]]-3D has been optimized to improve performance on multiprocessor vector computers.

There exists a up to now no Standard Validation Document for [[Trim|TRIM]]-3D which would provide the potential user with information about the capabilities and limitations of the [[model]].
==Preprocessors==
* [[Generation of Boundary Conditions]]
* [[Generation and Modification of Computational Grids]]
==Programs for Simulation==
* [[TR2VOR]]: generation of a compact version of the bathymetry-file together with some [[index]] arrays which are required during the simulation run for optimal performance on vector computers
* [[TR2LQ2]]: generation of a profile topography which is necessary to output results from a [[Trim|TRIM]]-3D simulation run along profiles
* [[TRIM-3D]]: simulation run
==Postprocessors==
* [[Conversion of Computed Results]]: general purpose prostprocessors for the conversion of data.
* [[Analysis of Calculated Results]]: tidal characteristic numbers, tide-independent characteristic numbers, tidal harmonic analysis and comparative analysis.
* [[EXCEL-Applications|Spread-Sheet Calculations for Computed Results]]: application of the spread-sheet program MS Excel (TM) to display and modify computed results.

* [[TR3MODATE]]: modification of date and time in a hydrodynamic results file if this hydrodynamic state should be used as initial state for a different date
* [[TR3KACHEL]]: generation of sections (tiles); topography as well as data are cut into pieces out of the result files for the entire computational domain for any desired section (tile).
* [[GVIEW2D]]: graphical display of time series at selected locations
* [[LQ2PRO]]: Visualization of data along profiles
* [[HVIEW2D]]: graphical display of 2D synoptic or data analyses results
* [[VVIEW2D]]: graphical representation of CFD-data for vertical sections
==General Data Flow==
[http://www.baw.de/downloads/wasserbau/mathematische_verfahren/Modellverfahren/pdf/trim3d-de.pdf Graphical representation] of general flow of data related to a [[Trim|TRIM]]-3D application (with German text only). This graphical representation is also available in [http://www.baw.de/downloads/wasserbau/mathematische_verfahren/Modellverfahren/eps/trim3d-de1.eps Encapsulated PostScript Format].
==Example Applications==
* [[Characteristic Numbers of Salinity (independent of tides)|tide independent characteristic numbers of salinity for a cross section in the Ems Estuary]].
* propagation of short waves in a [[harbour]] basin (text available in German only)
* Animations of salinity and flow velocity in the Außenems [[estuary]]
* [http://www.baw.de/downloads/wasserbau/mathematische_verfahren/Modellverfahren/pdf/trim3d-les.pdf A Second Order Lagrangian Method for Large Eddy Simulation]
* secondary currents in river turns, first results related to the project ''Minimierung der Unterhaltungsmaßnahmen im Bereich des Blexer Bogens'' (Lower Weser [[Estuary]]) --- available in German only

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