Updated 2012/12/26: Added link to published manuscript.

Updated 2012/11/19: Changes to reflect our accepted submission to Ocean Modelling.

As we have gained experience with the coupling of SWAN and ADCIRC, we have noticed that SWAN can focus wave energy due to excessive refraction in regions with coarse mesh resolution. Wave energy can become focused unrealistically at a single mesh vertex, causing the wave properties to become non-physical. In deep water, the significant wave heights can become 150m or larger. In shallow water, the peak wave periods can become 30s or larger, as the energy is pushed into the lowest-discretized frequency bin.

We have developed a few work-around solutions to this problem (Part 1 and Part 2). These solutions have enabled the wave refraction process in the region of interest, and disabled it elsewhere in the computational domain. For example, by enabling selectively the refraction in the northern Gulf of Mexico, we can obtain the following hindcast of the significant wave heights during Hurricane Gustav (2008).

Maximum significant wave heights (m) during Gustav (2008).

However, a more robust solution would be the limiting of the spectral propagation velocities, especially the directional turning rate, based on the Courant-Friedrichs-Lewy (CFL) condition. We have implemented recently these limiters in SWAN+ADCIRC. On this page, the limiters are introduced and tested on idealized and realistic applications.

It should be noted that these limiters are not a replacement for increased mesh resolution. The SWAN solution will always be better when the mesh is improved to represent the bathymetric gradients in the region of interest. However, when it is not feasible to increase the mesh resolution, then these limiters can control the largest SWAN errors without affecting the solution elsewhere.

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As we gain more experience with SWAN+ADCIRC, we have noticed a few minor issues with respect to actually running the coupled model. I have listed a few of them here, and I have described how to fix (or at least work around) each problem. Hopefully this page will be useful to new users of SWAN+ADCIRC.

This page will be updated as we encounter new issues. If you encounter an issue that belongs on this page, then please let me know. We want all simulations to step right along:

1. The pre-processor adcprep was not compiled for use with the coupled SWAN+ADCIRC.

This is a tricky error to debug when you first encounter it, because the code will write the following error message:

Input file missing

into either the screen output or the Errfile within each sub-directory. However, it is likely that all of the input files will be present in the run directory, including the SWAN input files (fort.26 and swaninit).

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