USER MANUAL SWAN Cycle III version 40.72A

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8 Chapter 2 below). Directions and spherical coordinates are in degrees ( 0 ) and not in radians. For the output of wave energy the user can choose between variance (m 2 ) or energy (spatial) density (Joule/m 2 , i.e. energy per unit sea surface) and the equivalents in case of energy transport (m 3 /s or W/m, i.e. energy transport per unit length) and spectral energy density (m 2 /Hz/Degr or Js/m 2 /rad, i.e. energy per unit frequency and direction per unit sea surface area). The wave−induced stress components (obtained as spatial derivatives of wave-induced radiation stress) are always expressed in N/m 2 even if the wave energy is in terms of variance. Note that the energy density is also in Joule/m 2 in the case of spherical coordinates. SWAN operates either in a Cartesian coordinate system or in a spherical coordinate system, i.e. in a flat plane or on a spherical Earth. In the Cartesian system, all geographic locations and orientations in SWAN, e.g. for the bottom grid or for output points, are defined in one common Cartesian coordinate system with origin (0,0) by definition. This geographic origin may be chosen totally arbitrarily by the user. In the spherical system, all geographic locations and orientations in SWAN, e.g. for the bottom grid or for output points, are defined in geographic longitude and latitude. Both coordinate systems are designated in this manual as the problem coordinate system. In the input and output of SWAN the direction of wind and waves are defined according to either • the Cartesian convention, i.e. the direction to where the vector points, measured counterclockwise from the positive x−axis of this system (in degrees) or • a nautical convention (there are more such conventions), i.e. the direction where the wind or the waves come from, measured clockwise from geographic North. All other directions, such as orientation of grids, are according to the Cartesian convention! For regular grids, i.e. uniform and rectangular, Figure 4.1 (in Section 4.5) shows how the locations of the various grids are determined with respect to the problem coordinates. All grid points of curvi-linear and unstructured grids are relative to the problem coordinate system. 2.6 Choice of grids, time windows and boundary / initial / first guess conditions 2.6.1 Introduction Several types of grids and time window(s) need to be defined: (a) spectral grid, (b) spatial (geographic) grids and time window(s) in case of nonstationary computations. The spectral grid that need to be defined by the user is a computational spectral grid on
which SWAN performs the computations. General definitions and remarks 9 SWAN has the option to make computations that can be nested in (coarse) SWAN, WAM or WAVEWATCH III. In such cases, the spectral grid need not be equal to the spectral grid in the coarse SWAN, WAM or WAVEWATCH III run. The spatial grids that need to be defined by the user are (if required): • a computational spatial grid on which SWAN performs the computations, • one (or more) spatial input grid(s) for the bottom, current field, water level, bottom friction and wind (each input grid may differ from the others) and • one (or more) spatial output grid(s) on which the user requires output of SWAN. The wind and bottom friction do not require a grid if they are uniform over the area of interest. For one-dimensional situations, i.e. ∂/∂y ≡ 0, SWAN can be run in 1D mode. If a uniform, rectangular computational spatial grid is chosen in SWAN, then all input and output grids must be uniform and rectangular too, but they may all be different from each other. If a curvi-linear computational spatial grid is chosen in SWAN, then each input grid should be either uniform, rectangular or identical to the used curvi-linear grid or staggered with respect to the curvi-linear computational grid. If an unstructured computational spatial grid is chosen in SWAN, then each input grid should be either uniform, rectangular or identical to the used unstructured grid. SWAN has the option to make computations that are nested in (coarse) SWAN, WAM or WAVEWATCH III. In such runs, SWAN interpolates the spatial boundary of the SWAN, WAM or WAVEWATCH III grid to the (user provided) grid of SWAN (that needs to (nearly) coincide along the grid lines of WAM or WAVEWATCH III or the output nest grid boundaries of SWAN). Since, the computational grids of WAM and WAVEWATCH III are in spherical coordinates, it is recommended to use spherical coordinates in a nested SWAN when nesting in WAM or WAVEWATCH III. SWAN using an unstructured mesh may be nested in SWAN employing a regular grid and vice versa. However, SWAN using an unstructured grid cannot be nested in WAM or WAVEWATCH III. Nesting from a 2D model to a 1D model is possible although is should not be done by using the commands NGRID and NEST. Instead, define the boundary point of the 1D model as an output point (using command POINTS) and write the spectra for that point using the command SPECout. In the 1D model, this spectra is used as boundary condition using
Page 1: SWAN USER MANUAL SWAN Cycle III ver
Page 5 and 6: Contents 1 Introduction 1 2 General
Page 7 and 8: TABLE . . . . . . . . . . . . . . .
Page 9 and 10: Chapter 1 Introduction The informat
Page 11 and 12: Chapter 2 General definitions and r
Page 13 and 14: General definitions and remarks 5 r
Page 15: General definitions and remarks 7 I
Page 19 and 20: General definitions and remarks 11
Page 27 and 28: Chapter 3 Input and output files 3.
Page 29 and 30: Chapter 4 Description of commands 4
Page 31 and 32: (h) Commands to write or plot outpu
Page 33 and 34: Description of commands 25 ’name
Page 35 and 36: Description of commands 27 Default:
Page 37 and 38: Description of commands 29 mesh. Th
Page 39 and 40: ⎛ ∆f = ⎝−1 + Description of
Page 41 and 42: Description of commands 33 • Easy
Page 43 and 44: Description of commands 35 grids ca
Page 45 and 46: Description of commands 37 y ′
Page 47 and 48: Description of commands 39 [fac]
Page 49 and 50: Description of commands 41 ’(10X,
Page 51 and 52: Description of commands 43 | | East
Page 53 and 54: Description of commands 45 CONSTANT
Page 55 and 56: Description of commands 47 points o
Page 57 and 58: Description of commands 49 CRAY WKS
Page 59 and 60: Description of commands 51 This com
Page 61 and 62: Description of commands 53 | JANSse
Page 63 and 64: Description of commands 55 [Csh3] c
Page 65 and 66: Description of commands 57 [ursell]
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Description of commands 59 [slope]
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Description of commands 61 [cgmod]
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Description of commands 63 < > [lim
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Description of commands 65 SIGIMPL
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Description of commands 67 ’sname
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Description of commands 69 (see bel
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Description of commands 71 [alpn] d
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Description of commands 73 ‘long
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| HSign | | | | HSWEll | | | | DIR
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Description of commands 77 | WLENgt
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Description of commands 79 QP DEPTH
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Description of commands 81 [tbegblk
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Description of commands 83 OUTput [
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Description of commands 85 If SWAN
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Description of commands 87 ACCUR MX
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Appendix A Definitions of variables
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Definitions of variables 91 RPER co
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Definitions of variables 93 WLEN Th
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Appendix B Command syntax B.1 Comma
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Repetitions of keywords and/or othe
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Required data and optional data Com
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Appendix C File swan.edt Below the
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File swan.edt 103 ! | -> DEFault !
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File swan.edt 105 ! FRAME ’sname
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Appendix D Spectrum files, input an
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0.3892E-03 192.0 15.2 0.8007E-03 24
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Spectrum files, input and output 11
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Spectrum files, input and output 11
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Bibliography [1] SWAN - Implementat
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117 longitude, 8, 27, 49, 50, 85, 1
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