The Boussinesq model is a kind of wave model widely used in near-shore engineering, and its computational accuracy mainly depends on the basic performance of the model, while the upper bound of nonlinear application of the model has always been the focus of attention. In recent years, the two-layer Boussinesq model has gained great progress regarding theoretical properties, numerical modeling and applications. However, the value of its nonlinear upper bound has not been given in any literature. So in this study, the stream-function of the two-layer Boussinesq model was solved using a combination of genetic algorithm and Newton's method to determine the upper bound value of the model, considering the highest spatial derivatives of order 3 and 5. In the same way, the stream-function solutions of the corresponding one-layer Boussinesq model were derived. The numerical results show that the nonlinear upper bounds of the two-layer Boussinesq model with the highest derivatives of order 3 and 5 are H/L = 0.137 and 0.138. Compared with the one-layer Boussinesq model, the two-layer model has a greater water depth of applicability regarding strong nonlinear characteristics. The combination of genetic algorithm and Newton's method proposed in this study can provide some references for solving the stream-function waves of the related Boussinesq models.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |