  Detailed studies of the azimuthal dependence of the mean fragment and flow
energies in the Au+Au and Xe+CsI systems are reported as a function of incident
energy and centrality. Comparisons between data and model calculations show
that the flow energy values along different azimuthal directions could be
viewed as snapshots of the fireball expansion with different exposure times.
For the same number of participating nucleons more transversally elongated
participant shapes from the heavier system produce less collective transverse
energy. Good agreement with BUU calculations is obtained for a soft nuclear
equation of state.
