USER MANUAL SWAN Cycle III version 40.72A

Description of commands 55
[Csh3]
coefficient for shallow water scaling in case of DIA.
Default: [Csh3]=−1.25.
BREaking CONSTANT [alpha] [gamma]
With this command the user can influence depth-induced wave breaking in shallow water
in the SWAN model.
If this command is not used, SWAN will account for wave breaking anyhow (with default
options and values). If the user wants to specifically ignore wave breaking, he should use
the command: OFF BREAKING.
CONSTANT
[alpha]
[gamma]
indicates that a constant breaker parameter is to be used.
proportionality coefficient of the rate of dissipation.
Default: [alpha] = 1.0.
the ratio of maximum individual wave height over depth.
Default: [gamma] = 0.73.
| -> JONswap [cfjon]
|
FRICTION < COLLins [cfw]
|
| MADsen [kn]
With this optional command the user can activate bottom friction. If this command is not
used, SWAN will not account for bottom friction.
In SWAN three different formulations are available, i.e., that of Hasselmann et al. (1973,
JONSWAP), Collins (1972), and Madsen et al. (1988). The default option is: JONSWAP.
JONSWAP
[cfjon]
COLLINS
indicates that the semi-empirical expression derived from the JONSWAP results
for bottom friction dissipation (Hasselmann et al., 1973, JONSWAP) should be
activated. This option is default.
coefficient of the JONSWAP formulation. [cfjon] is equal to 0.038m 2 s −3 for
swell conditions (Hasselmann et al., 1973) and equal to 0.067m 2 s −3 for wind
sea conditions.
Default: [cfjon] = 0.067.
indicates that the expression of Collins (1972) should be activated.