  Elliptic flow has been one of the key observables for establishing the
finding of the quark-gluon plasma (QGP) at the highest energies of Relativistic
Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). As a sign of
collectively behaving matter, one would expect the elliptic flow to decrease at
lower beam energies, where the QGP is not produced. However, in the recent RHIC
beam energy scan, it has been found that the inclusive charged hadron elliptic
flow changes relatively little in magnitude in the energies between 7.7 and 39
GeV per nucleon-nucleon collision. We study the collision energy dependence of
the elliptic and triangular flow utilizing a Boltzmann + hydrodynamics hybrid
model. Such a hybrid model provides a natural framework for the transition from
high collision energies, where the hydrodynamical description is essential, to
smaller energies, where the hadron transport dominates. This approach is thus
suitable to investigate the relative importance of these two mechanisms for the
production of the collective flow at different values of beam energy. Extending
the examined range down to 5 GeV per nucleon-nucleon collision allows also
making predictions for the CBM experiment at FAIR.
