Euler equations

Summary

The Euler equations describe the motion of an ideal fluid, that is, a fluid without viscosity. They express conservation of mass and Newton's second law for each parcel of fluid, with pressure as the only internal force. The incompressible Euler equations are the case $\nu = 0$ of the Navier–Stokes equations. They were among the first partial differential equations written down, and many questions about them are still open.