On nonlinear extrapolation of the linear wave theory for shallow flows

Linear wave theory provides a satisfactory mathematic tool only for waves of a very low amplitude. The authors have to consider acceptable nonlinear extrapolation of this theory. Their attempts to estimate wave resistance of a ship in deep water was successful only due to nonlinear extrapolation of wave amplitude. However, for shallow water the nonlinear theory predicts a considerable increase in wavelengths. In this case the authors have to perform calculations for some “effective” Froude number, using its real value for amplitude corrections