Abstract
Numerous efforts have been made for the improvement of nonlinear energy transfer computation. Until now, the DIA method is generally used for evaluating nonlinear energy transfer Snl in the practical wave model because of its low computational cost. Tamura et al. (2008), suggested SRIAM developed by Komatsu (1996) to be incorporated into the operational wave model. The performances of the wave model were significantly improved by using SRIAM. However, the computational cost is still 20 times larger than the existing operational wave model using DIA. Therefore, we modified SRIAM by reducing the number of the resonant configurations. It was found that 9 numbers of configurations produce the nonlinear energy transfer approximately well as compared to the original SRIAM which has 20 numbers of configurations. This method is then called as the Reduced SRIAM (R-SRIAM). The configurations of R-SRIAM show that the quasi-singular quadruplets contribute the most to the nonlinear energy transfer than the regular quadruplets. Hence, we proposed the efficient number of resonance configurations by selecting only from the quasi-singular quadruplets to be included in the calculation, which is called as the Alternative Multiple DIA (AM-DIA) method. The reduced number of the resonant configurations makes the computational method of the nonlinear energy transfer more economically acceptable.
