3+1 dimensional viscous hydrodynamics at high baryon densities

A 3 + 1 dimensional event-by-event viscous hydrodynamic + cacade model is applied for the simulation of heavy ion collision reactions at root(NN)-N-S = 6.3 ... 200 GeV. UrQMD cascade is used for the pre-thermal (pre-hydro) and final (post-hydro) stages of the reaction. The baryon, as well as electric charge densities are consistently taken into account in the model. For this aim the equation of state based on a Chiral model coupled to the Polyakov loop is used in hydrodynamic phase of evolution. As a result of the model adjustment to the experimental data, the effective values of the shear viscosity over entropy density eta/s are obtained for different collision energies in the BES region. A decrease of the effective values of eta/s from 0.2 to 0.08 is observed as collision energy increases from root s approximate to 7 to 39 GeV.