  We explore the evolution of the large-scale anisotropy in the velocity field
caused by the gravitational pancaking effect assuming a LCDM universe. The
Millennium Run halo catalogs at four different redshifts, z=0, 0.5, 1 and z=2
are analyzed to find that the pancaking effect starts to intervene the
hierarchical structure formation at redshift z=2 when a characteristic pancake
scale is around 3 Mpc/h. It is also clearly shown how the degree and scale of
the pancaking effect changes with time. An analytic model based on the
Zel'dovich approximation is presented to explain quantitatively the evolution
of the velocity-pancake alignment. A cosmological implication of our finding
and a possibility of detecting a signal in real universe are discussed.
