The applicability of nonlinear theories of the internal solitary wave and its loads on slender body by experimental methods

It is essential to give the applicable range of nonlinear theories of the internal solitary wave in different classification conditions and water depth. The nonlinear theories used to describe the ISW, including KdV, eKdV and MCC theories were compared with experimental results. The characteristic parameters of ISW (waveform, phase speed, and wave frequency) and its load on slender body were chosen to provide a quantitatively applicable range of three nonlinear theories at different water depths. In general, the optimal theories are KdV, eKdV and MCC in turns for most conditions. However, for the description of phase speed, both the eKdV and MCC theories can describe it well, where the KdV theory has a large error in describing phase speed at large ISW amplitude. For the vertical force, the KdV and eKdV theories can describe it well in turns, while the MCC theory has a large error in calculating the vertical force. A diagram of the applicable range under different classification conditions and at different water depths is proposed for choosing a better theory in different fields.