  The present work investigates the direct interaction of sheared mean flow
with zonal flows (ZF) and the effect of parallel ion motion on ZF generation in
ion-temperature-gradient (ITG) background turbulence. An analytical model for
the direct interaction of sheared mean flows with zonal flows is constructed.
The model used for the toroidal ITG driven mode is based on the equations for
ion continuity, ion temperature and parallel ion motion whereas the ZF
evolution is described by the vorticity equation. The behavior of the ZF growth
rate and real frequency is examined for typical tokamak parameters. It is shown
that in general the zonal flow growth rate is suppressed by the presence of a
sheared mean flow. In addition, with parallel ion motion effects the ZFs become
more oscillatory for increasing $\eta_i (= L_n/L_{Ti})$ value.
