Compressible flow

Summary

Compressible flow is the flow of a fluid in which changes of density are significant and must be computed together with the velocity and pressure. It is the regime of gases at speeds comparable to the speed of sound, and its main parameter is the Mach number. Its equations, the compressible Euler and Navier–Stokes equations, couple mass, momentum and energy through an equation of state. New phenomena appear that have no counterpart in incompressible flow, such as shock waves and choking.