Model:SWAN: Difference between revisions
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|Spatialscale=Continental, Regional-Scale, Landscape-Scale | |Spatialscale=Continental, Regional-Scale, Landscape-Scale | ||
|One-line model description=SWAN is a third-generation wave model | |One-line model description=SWAN is a third-generation wave model | ||
|Extended model description= | |Extended model description=SWAN is a third-generation wave model that computes random, short-crested wind-generated waves in coastal regions and inland waters. | ||
SWAN is a third-generation wave model that computes random, short-crested wind-generated waves in coastal regions and inland waters. | |||
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{{Model technical information | {{Model technical information | ||
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{{Input - Output description | {{Input - Output description | ||
|Describe input parameters=The bathymetry, current, water level, bottom friction and wind (if spatially variable) need to be provided to SWAN on so-called input grids. It is best to make an input grid so large that it completely covers the computational grid. | |Describe input parameters=The bathymetry, current, water level, bottom friction and wind (if spatially variable) need to be provided to SWAN on so-called input grids. It is best to make an input grid so large that it completely covers the computational grid. | ||
|Input format=Binary | |Input format=Binary | ||
|Describe output parameters=SWAN can provide output on uniform, recti-linear spatial grids that are independent from the input grids and from the computational grid. In the computation with a curvi-linear computational grid, curvi-linear output grids are available in SWAN. This also holds for triangular meshes. An output grid has to be specified by the user with an arbitrary resolution, but it is of course wise to choose a resolution that is fine enough to show relevant spatial details. It must be pointed out that the information on an output grid is obtained from the computational grid by bi-linear interpolation (output always at computational time level). This implies that some inaccuracies are introduced by this interpolation. It also implies that bottom or current information on an output plot has been obtained by interpolating twice: once from the input grid to the computational grid and once from the computational grid to the output grid. If the input-, computational- and output grids are identical, then no interpolation errors occur. | |Describe output parameters=SWAN can provide output on uniform, recti-linear spatial grids that are independent from the input grids and from the computational grid. In the computation with a curvi-linear computational grid, curvi-linear output grids are available in SWAN. This also holds for triangular meshes. An output grid has to be specified by the user with an arbitrary resolution, but it is of course wise to choose a resolution that is fine enough to show relevant spatial details. It must be pointed out that the information on an output grid is obtained from the computational grid by bi-linear interpolation (output always at computational time level). This implies that some inaccuracies are introduced by this interpolation. It also implies that bottom or current information on an output plot has been obtained by interpolating twice: once from the input grid to the computational grid and once from the computational grid to the output grid. If the input-, computational- and output grids are identical, then no interpolation errors occur. | ||
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In nonstationary computations, output can be requested at regular intervals starting at a given time always at computational times. | In nonstationary computations, output can be requested at regular intervals starting at a given time always at computational times. | ||
|Output format=Binary | |Output format=Binary | ||
|Pre-processing software needed?=No | |Pre-processing software needed?=No | ||
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* Transmission through and reflection (specular and diffuse) against obstacles. | * Transmission through and reflection (specular and diffuse) against obstacles. | ||
* Diffraction. | * Diffraction. | ||
|Describe key physical parameters and equations=SWAN contains a number of physical processes (see Scientific/Technical documentation) that add or withdraw wave energy to or from the wave field. The processes included are: wind input, whitecapping, bottom friction, depth-induced wave breaking, obstacle transmission, nonlinear wave-wave interactions (quadruplets and triads) and wave-induced set-up. SWAN can run in several modes, indicating the level of parameterization. SWAN can operate in first-, second- and third-generation mode. The first- and second-generation modes are essentially those of Holthuijsen and De Boer (1988); first-generation with a constant Phillips "constant" of 0.0081 and second-generation with a variable Phillips "constant". An overview of the options is given in Table below. | |||
|Describe key physical parameters and equations=SWAN contains a number of physical processes (see Scientific/Technical documentation) that add or withdraw wave energy to or from the wave field. The processes included are: wind input, whitecapping, bottom friction, depth-induced wave breaking, obstacle transmission, nonlinear wave-wave interactions (quadruplets and triads) and wave-induced set-up. SWAN can run in several modes, indicating the level of parameterization. SWAN can operate in first-, second- and third-generation mode. The first- and second-generation modes are essentially those of Holthuijsen and De Boer (1988); first-generation with a constant Phillips "constant" of 0.0081 and second-generation with a variable Phillips "constant". An overview of the options is given in Table below. | |Describe length scale and resolution constraints=SWAN can be used on any scale relevant for wind generated surface gravity waves. However, SWAN is specifically designed for coastal applications that should actually not require such flexibility in scale. The reasons for providing SWAN with such flexibility are: | ||
|Describe length scale and resolution constraints= | |||
SWAN can be used on any scale relevant for wind generated surface gravity waves. However, SWAN is specifically designed for coastal applications that should actually not require such flexibility in scale. The reasons for providing SWAN with such flexibility are: | |||
* to allow SWAN to be used from laboratory conditions to shelf seas and | * to allow SWAN to be used from laboratory conditions to shelf seas and | ||
* to nest SWAN in the WAM model or the WAVEWATCH III model which are formulated in terms of spherical coordinates. | * to nest SWAN in the WAM model or the WAVEWATCH III model which are formulated in terms of spherical coordinates. | ||
|Describe any numerical limitations and issues='''Limitations''' | |Describe any numerical limitations and issues='''Limitations''' | ||
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In areas where variations in wave height are large within a horizontal scale of a few wave lengths, diffraction should be used. However, the computation of diffraction in arbitrary geophysical conditions is rather complicated and requires considerable computing effort. To avoid this, a phase-decoupled approach is employed in SWAN so that same qualitative behaviour of spatial redistribution and changes in wave direction is obtained. This approach, however, does not properly handle diffraction in harbours or in front of reflecting obstacles. | In areas where variations in wave height are large within a horizontal scale of a few wave lengths, diffraction should be used. However, the computation of diffraction in arbitrary geophysical conditions is rather complicated and requires considerable computing effort. To avoid this, a phase-decoupled approach is employed in SWAN so that same qualitative behaviour of spatial redistribution and changes in wave direction is obtained. This approach, however, does not properly handle diffraction in harbours or in front of reflecting obstacles. | ||
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{{Model testing | {{Model testing | ||
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# Van der Westhuysen, A.J., 2009, Modelling of depth-induced wave breaking under finite-depth wave growth conditions, J. Geophys. Res., in press. | # Van der Westhuysen, A.J., 2009, Modelling of depth-induced wave breaking under finite-depth wave growth conditions, J. Geophys. Res., in press. | ||
# Zijlema, M., 2009, Computation of wind-wave spectra in coastal waters with SWAN on unstructured grids, Coastal Engineering, in press. | # Zijlema, M., 2009, Computation of wind-wave spectra in coastal waters with SWAN on unstructured grids, Coastal Engineering, in press. | ||
|Manual model available=Yes | |Manual model available=Yes | ||
|Model website if any=Manual: http://130.161.13.149/swan/online_doc/swanuse/swanuse.html | |Model website if any=Manual: http://130.161.13.149/swan/online_doc/swanuse/swanuse.html | ||
Official SWAN website: www.swan.tudelft.nl | Official SWAN website: http://www.swan.tudelft.nl | ||
|Model forum=http://130.161.13.149/swan/forum/default.asp | |Model forum=http://130.161.13.149/swan/forum/default.asp | ||
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Revision as of 13:57, 22 November 2009
Contact
Name | Team SWAN |
Type of contact | Model developer |
Institute / Organization | Delft University of Technology, Faculty of Civil Engineering and Geosciences |
Postal address 1 | P.O. Box 5048 |
Postal address 2 | |
Town / City | Delft |
Postal code | 2600 GA |
State | NO STATE |
Country | The Netherlands"The Netherlands" is not in the list (Afghanistan, Albania, Algeria, Andorra, Angola, Antigua and Barbuda, Argentina, Armenia, Australia, Austria, ...) of allowed values for the "Country" property. |
Email address | swan-info-citg@tudelft.nl |
Phone | |
Fax |
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