The wave model SWAN

SWAN is the most widely used computer model to compute irregular waves in coastal environments, based on deep water wave conditions, wind, bottom topography, currents and tides (deep and shallow water).
SWAN explicitly accounts for all relevant processes of propagation, generation by wind, interactions between the waves and decay by breaking and bottom friction. Diffraction is included in an approximate manner in SWAN.
The computer code of SWAN is available in public domain through the website of Delft University of Technology.
We offer an executable version for a PC under WINDOWS, which is identical to the version distributed by Delft University numerically; it produced identical results with identical input data. However, the version of SWAN by DHH has a number of powerful graphical output facilities. It has the line plot capabilities that were available in older SWAN versions, but now scalar quantities can also be represented by colored areas. The same is true for 2-dimensional spectra. In the sequel the SWAN version distributed by DHH is called SWAN-DHH.
This version is available in combination with a hyperlinked User Manual for SWAN-DHH.

Analysis tools in SWAN

SWAN is exceptional among the codes used in engineering in the sense that it provides many tools that help the user to analyse the results of a computation, thanks to its origin in an academic environment. While other codes only produce the wave parameters in the area of interest to the client, SWAN is able to show the contributions of the various terms in the spectral wave equations and the behaviour of various quantities during the iterative process.
The SWAN course gives numerous suggestions on how to use the analysis tools, and what data should be studied during the initial phase of an engineering project. The course also shows how the graphics extension can be used to visualise these data.
It is stressed that the analysis tools are valuable not only to students and researchers, but also to consultants if they have to explain to their client how certain results are obtained.

Graphical output from SWAN-DHH

One of the advantages of SWAN-DHH is that it provides options to produce pictures of the computed wave parameters directly from the program itself. The plotting facilities that used to be available in version 40.11 of SWAN have now been extended. In addition to plotting in HPGL (Hewlett-Packard Plotting Language) SWAN-DHH can provide pictures in PostScript.
Using PostScript it also has become possible to generate colored pictures which can be used for presentation to principals, managers and the general public. The picture at the right shows values of significant wave height in the Haringvliet area in the Netherlands, together with arrows showing the average wave direction.

SWAN-DHH can also show 2-d spectra (spectral energy density as function of frequency and direction) in colors, and optionally, like older SWAN versions, with black line plots.

See also the possibilities of the post-processing package OPGraph.


the SWAN-DHH user manual

The SWAN-DHH user manual is a modern hyperlinked manual, where all necessary information can easily be found by simple mouse-clicks. For the description of SWAN commands that are in the public-domain SWAN it refers to the online manual by Delft University.
The manual contains a brief introduction of the theory underlying the model. It also provides a link to the new SWAN course enabling inexperienced users to develop themselves into efficient wave modelers.

  ©: Nico Booij (2012)