Abstract
Basic performance of the SWAN model with 4 modes related to stationarity and dimension is investigated through numerical simulations under given uniform winds blowing normally to a coastline. The main accomplishments are as follows; (1) The stationary(st) and nonstationary(nst) modes yield a slightly different wave growth and the one dimensional(1d) and two dimensional(2d) modes give almost the same wave growth. (2) The Westhuysen et al.(2007) results regarding the relation between dimensionless wave energy ε* or dimensionless peak frequency f*p and dimensionless fetch F* are well reproduced by use of a st-1d mode with coefficient δ = 0 in the dissipation term. However, the ratio of peak period to moment basedmean period with -1 order is much greater than the empirical value of 1.05. (3) Wave growth is strongly affected by the choice of δ and time increment Δt used in nst mode. (4) Wave growth curves by nst-2d mode with δ = 1 are almost free from the given wind speed and provide overgrowth of both the Westhuysen et al.(2007) results and the empirical results, whereas the wave period ratio is much closer to an empirical value of 1.05. (5) The Toba constant BT of 0.062 in 3/2 power law may be roughly reproduced by nst-mode with δ = 1, although the calculated coefficient varies within a range of ±5 % for mean of 0.070.
