Generation of solitary waves in a three-layer fluid system

Based on the generalized Boussinesq equations for the three-layer fluid system, the KdV equations for the interfaces are obtained by using a perturbation method and the effect of fluid depth on the generation of solitary waves is discussed. By classifying the waves into fast-, medium- and slow-modes, it is found that the results on the slow-mode waves is qualitatively consistent with the experimental ones, and there may exist concave solitary waves on free surface, which is yet to be verified by experiments.