Interactions of internal solitary waves in deep stratified fluids (I)——Weak interactions

<正> The weak interactions of internal solitary waves in deep stratified fluids are investigated interms of Lagrangian coordinates, which include the head-on and overtaking collisions of solitary waves with. different modes, and the head-on collision of waves with the same mode. The analysis shows that each waveis governed by the intermediately long wave (ILW) equation for finitely deep fluids and the Benjamin-Ono(BO) equation for infinitely deep fluids. The main effect of the interaction is the phase shifts of each wave.