On the Hamilton's principle for perfect fluids

The paper deals with a new formulation of Hamilton's principle for perfect fluids. The discussion is confined to the Lagrangian description of fluid motion that is based on the positions of fluid particles. The derivation of the principle is compared with earlier treatments of the problem existing in literature of the subject. It is the author's impression that the proposed solution is better than those encountered in previous treatements since the latter obscure a physical meaning of the principle. In addition, the present formulation takes into account the fluid boundary which was left out of account in that earlier approaches. The last feature is especially important in analysing fluid-structure interaction problems when variation of displacements of the fluid boundary changes the energy of the mentioned system.