NUMERICAL STUDY ON FREQUENCY DOWNSHIFT OF GRAVITY WAVE SPECTRA IN DEEP AND INTERMEDIATE WATER DEPTHS DUE TO NONLINEAR ENERGY TRANSFER

[摘要] Frequency downshift of gravity wave spectra in deep and finite water depths due to the nonlinear energy transfer are discussed. In deep water depths, numerical computations of the nonlinear energy transfer are performed with DIA (Hasselmann et al., 1985), RIAM (Komatsu et al., 1993) and SRIAM (Komatsu et al., 1996). Then, differences in temporal changes of directional spectra computed with a modified WAM implemented with RIAM and SRIAM are compared with those computed with the original WAM implemented with DIA. In finite water depth, numerical computations are performed with a modified WAM implemented with FD-RIAM (Hashimoto, et al., 2002), an exact method, which was upgraded from an earlier version (Hashimoto et al., 1998) based on Komatsu et al., (2001). Differences in frequency downshift of gravity wave spectra in deep and finite water depths are discussed based on the numerical results for various directional spectra in various water depths.

[学科分类] 建筑学

[关键词] nonlinear energy transfer;frequency downshift;wave modeling