  We study effects of eccentricity fluctuations on the elliptic flow
coefficient v_2 at mid-rapidity in both Au+Au and Cu+Cu collisions at
sqrt{s_NN}=200 GeV by using a hybrid model that combines ideal hydrodynamics
for space-time evolution of the quark gluon plasma phase and a hadronic
transport model for the hadronic matter. For initial conditions in hydrodynamic
simulations, both the Glauber model and the color glass condensate model are
employed to demonstrate the effect of initial eccentricity fluctuations
originating from the nucleon position inside a colliding nucleus. The effect of
eccentricity fluctuations is modest in semicentral Au+Au collisions, but
significantly enhances v_2 in Cu+Cu collisions.
