Derivation of fluid dynamics from kinetic theory with the 14--moment approximation

Understand

We review the traditional derivation of the fluid-dynamical equations from kinetic theory according to Israel and Stewart.

• We show that their procedure to close the fluid-dynamical equations of motion is not unique.
• Their approach contains two approximations, the first being the so-called 14-moment approximation to truncate the single-particle distribution function.
• The second consists in the choice of equations of motion for the dissipative currents.