Invariance Properties of Inviscid Fluids of Grade n
  Fluids of grade n are continuous media in dynamic changes of phases avoiding the surfaces of discontinuity and representing the capillary layers in liquid-vapour interfaces. We recall the thermodynamic form of the equation of motion for inviscid fluids of grade n. First integrals and theorems of circulation are deduced. A general classification of flows is proposed. 
Pierre Casal, Henri Gouin (MSNMGP, LMMT)