  The main object of the paper is to present the condition of the non-diffusive
part of the Reynolds stress for driving the double-cell structure of the solar
meridional circulation, which has been revealed by recent helioseismic
observations. By conducting a set of mean-field hydrodynamic simulations, we
confirm for the first time that the double-cell meridional circulation can be
achieved along with the solar-like differential rotation when the Reynolds
stress transports the angular momentum upward in the lower part and downward in
the upper part of the convection zone. It is concluded that, in a stationary
state, the accumulated angular momentum via the Reynolds stress in the middle
layer is advected to both the upper and lower parts of the convection zone by
each of the two meridional circulation cells, respectively.
