Hydrodynamic conservation integrals for galaxies

Summary This paper supplements and extends previous discussions of galaxies in the light of meteorological theory by including explicitly the effect of random motions in a star gas. The conservation integrals for momentum and kinetic energy are formulated and the kinetic energy is further partitioned into kinetic energy of the large scale flows and kinetic energy of the random star motions. The kinetic energy of the random star motions is analogous to the internal energy in an ordinary gas and is transformed into kinetic energy of the fluid flow according to a law which is a generalization of the first law of thermodynamics as applied to fluids. It is possible to make more detailed division of the kinds of energy and their laws of transformation.