We study the influence of a temperature-dependent shear viscosity over entropy density ratio $\eta /s$, different shear relaxation times ${\tau }_{\pi }$, as well as different initial conditions on the transverse momentum spectra of charged hadrons and identified particles. We investigate the azimuthal flow asymmetries as a function of both collision energy and centrality. The elliptic flow coefficient turns out to be dominated by the hadronic viscosity at RHIC energies. Only at higher collision energies the impact of the viscosity in the QGP phase is visible in the flow asymmetries. Nevertheless, the shear viscosity near the QCD transition region has the largest impact on the collective flow of the system. We also find that the centrality dependence of the elliptic flow is sensitive to the temperature dependence of $\eta /s$.

• Received 22 March 2012

DOI:https://doi.org/10.1103/PhysRevC.86.014909