摘要: When certain types of waves inherit a gentle nonuniformity or experience long scale variations in the medium they respond by slow variation their characteristics without substantial disintegration loss identity. A standard example is refraction linear sinusoidal surface due to changes bathymetry current. Also few classes nonlinear display similar behaviour; like Stokes (Peregrine 1983), shocks (Whitham 1974) and Boussinesq solitons (Miles 1977b). The latter concern present work