Hydrodynamic anomalies in supercritical fluid

Using the molecular dynamics simulations we investigate properties of velocity autocorrelation function of Lennard-Jones fluid at long and intermediate time scales in wide ranges of temperature and density. We show that the amplitudes of both the leading and the subleading time asymptotic terms of velocity autocorrelation function, a(1) and a(2), show essentially non-monotonic temperature and density dependence. There are two lines on temperature-density plain corresponding to maxima of a(1) (a(2)) along isochors and isotherms situated in the supercritical fluid (hydrodynamic anomalies). These lines give insight into the stages of the fluid evolution into gas. (C) 2014 AIP Publishing LLC.