Of or pertaining to → hydrostatics.
Fr.: équation hydrostatique
The equation describing the → hydrostatic equilibrium in a star, expressed as: dP/dr = -GMρ/r2, where P and M are the mass and pressure of a spherical shell with thickness dr at some distance r around the center of the star, ρ is the density of the gas, and G the → gravitational constant.
→ hydrostatic; → equation.
Fr.: équilibre hydrostatique
1) The physical situation reached in a fluid when complete balance exists between
the internal pressure at any point and the weight of the material above the point.
→ hydrostatic; → equilibrium.
Fr.: halo hydrostatique
A model of the → Milky Way galaxy in which the → Galactic halo (composed of → gas, → magnetic fields, and → cosmic rays) is assumed to be in → hydrostatic equilibrium. Parker (1966) presented the first study of stability considerations between gas, magnetic fields and cosmic rays in an equilibrium configuration. He found that it is difficult to maintain a stable configuration due to magnetohydrodynamic self-attraction (→ Parker instability). Subsequent works taking into account turbulent motions showed that turbulent pressure can mitigate the influence of Parker instabilities. This enabled new attempts to find conditions under which a stable equilibrium configuration of the Galaxy could exist.
→ hydrostatic; → halo.
Fr.: pression hydrodynamique
The term ρgz in the → Bernoulli equation. It is not pressure in a real sense, because its value depends on the reference level selected.
→ hydrostatic; → pressure.
A branch of physics that deals with the characteristics of → fluids at rest and especially with the pressure in a fluid or exerted by a fluid on an immersed body.