Abstract
The inviscid equations for compressible flows predict the occurence of singularities after a finite time for a large class of smooth initial data[1]. Based upon the hyperbolic nature of these equations, the method of characteristics allows a detailed study of this phenomenon in one spatial dimension. Qualitatively speaking, the formation of discontinuities is related to the fact that perturbations with a larger amplitude move faster and pile up on lower amplitude perturbations. Thus, smooth initial data may produce after a finite time infinitely sharp density and/or velocity variations. This violates a basic assumptions of continuous hydrodynamics: any field as the mass density or the fluid velocity must be almost constant on molecular scales, that is on a mean free path in gases which I shall consider from now on.

This publication has 5 references indexed in Scilit: