| Astrophysics (Index) | About |
Hydrodynamic equations are equations that describe fluid dynamics, relating velocity, mass, momentum, and pressure. The Navier-Stokes equations provide a very general framework, which may be made more specific by plugging in the characteristics of the forces, e.g., gravity, and the fluids, e.g., an astronomical body atmosphere or surface liquid. For (approximately) spherically-symmetric flows, e.g., the solar wind, it can be the equation of hydrostatic equilibrium with modifications to handle the motion.