Spectral modelling of typhoon-generated waves in shallow waters: Approche spectrale des vagues engendrees par des typhons en eau peu profonde

Field data obtained in the measurement of typhoon-generated waves in Gulf of Bei Bu, a semi-enclosed shallow water bay, is used in the validation of a ‘third generation’ spectral model which employs an accurate numerical solution algorithm. The linear bottom dissipation expression obtained in the JONSWAP study is adopted since it produces a more reasonable wave growth characteristics in an ideal test case as compared to the dissipation formulation based on quadratic friction law. Computational efficiency of the model is enhanced by employing digital filtering technique to suppress the numerical instability arisen from using large time step (up to about 30 minutes) and to maintain an acceptable accuracy. The performance of the model is good and provides a further support to the ‘third generation’ formulation of spectral models.