  Decorrelation of the elliptic flow in rapidity is calculated within a hybrid
approach which includes event-by-event viscous fluid dynamics and final state
hadronic cascade model. The simulations are performed for Au+Au collisions at
center-of-mass collision energies of 27 and 200 GeV per nucleon pair, as well
as various colliding systems at 72 GeV per nucleon pair. Initial conditions
determined by an extended Monte Carlo Glauber model show better agreement with
experimental data than initial conditions from the UrQMD transport model. We
show how the observed decorrelation is connected with the decorrelation of
initial state spatial anisotropies. We also study how the effect is increased
by the final state hadronic cascade.
