Directional distribution
Spectral plot
Swan Support Package

Graphics Extension for SWAN

SWAN is the most powerful and the most widely used software for the simulation of waves in the coastal zone. The latest news on SWAN can be found on the SWAN website maintained by the SWAN team of Delft University of Technology.

One of the drawbacks of the SWAN version by Delft University is that it produces only numerical output. For most users it is essential that they get graphical output in order to be able to interpret the results of the computations. Unlike most post-processing systems the graphics extension by DHH is integrated with the SWAN software itself so that graphical output can be obtained for all output quantities known in SWAN and more quickly than with other systems. This facility greatly enhances quality control and is therefore indispensable for consulting companies. In educational environments graphics is an important tool to provide insight in wave dynamics to students.

The graphics extension can produce files with two different formats: HPGL (Hewlett-Packard Graphics Language) and Postscript. DHH does not deliver viewers for these files but most graphics software is able to visualise one or both of these formats. The Graphical User Interface for SWAN contains a simple HPGL viewer.

The Swan Support Package contains an executable SWAN with graphics extension, but only for single-processor execution on the Windows platform. Users who need a version for Unix or a multi-processor version, can obtain a description of the procedure how to generate such a version, and the source code for the plotting procedures by downloading the package with the test bank. It is appreciated if such users make their executable available to other SWAN users.

Many output parameters

SWAN with graphics extension can produce colored pictures for all scalar quantities known in SWAN, so not only the well-known parameters such as significant wave height and average period, but also swell wave height, dissipation, directional spreading and many others. In order to verify the input quantities used in the computation the bottom level, water level etc. can be shown as well.
These colored pictures can be combined with vector fields, e.g. for average wave direction, wave-driven forces (important for long-shore currents), energy transport etc. and for verification of input: wind field or current field.

Plot of directional distribution

A unique feature of the graphical extension is the so-called “star” plot. This shows the directional distribution of the energy transport for a large number of points in space. It enables users to reconstruct how the wave energy is flowing through the region. Also it enables users to see whether a large directional spreading is due to the presence of cross-seas.

spectral plots

A third option of the graphics extension is the production of plots of 1-d and 2-d spectra. For every output location indicated by the user SWAN can make a page showing a colored representation of the 2-d spectrum (energy density as function of frequency and direction). Also a line graph of the 1-d (frequency-) spectrum is presented, together with a number of overall wave parameters for the same location.
The post-processing software OPGraph is able to show the spectral distribution of source terms such as whitecapping or quadruplets. OPGraph was designed to generate graphs where results of different SWAN runs can be intercompared or where SWAN runs are compared with observations.

Swan Support Package

The SWAN course is delivered together with the Graphical User Interface for SWAN, the newest SWAN version ([version]) with graphics extension and OPGraph. This package is available free of charge; please fill in the order form.
The package is available only for MS-Windows based systems.

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  ©: Nico Booij (2012)