Classical fluids[1] are systems of particles which retain a definite volume, and are at sufficiently high temperatures (compared to their Fermi energy) that quantum effects can be neglected.
On heating it undergoes an evaporation transition and becomes a classical gas that obeys Boltzmann statistics.
A system of charged classical particles moving in a uniform positive neutralizing background is known as a one-component plasma (OCP).
An essentially very accurate way of determining the properties of classical fluids is provided by the method of molecular dynamics.
Such non-classical Fermi systems, i.e., quantum fluids, can be studied using quantum Monte Carlo methods, Feynman path integral formulation, and approximately via CHNC integral-equation methods.