We study the energy dependence of collective (hydrodynamic-like) nucle
ar matter flow in (400-1970)A MeV Ni + Au and (1000-1970)A MeV Ni + Cu
reactions. The flow increases with energy, appears to reach a maximum
, and then to decrease at higher energies. A way of comparing the ener
gy dependence of flow values for different projectile-target mass comb
inations is introduced, which demonstrates a more-or-less common scali
ng behavior among flow values from different systems.