  The expansion of the rotating fluid will change the vorticity and rotational
speed of the expanding region. In turbulent thermal convection, this
microscopic effect is preserved. Tracking the fluid micelles shows that the
average vorticity varies with density, producing vorticity transport and
angular momentum transport from the low-density area to the high-density area,
forming a macroscopic vorticity difference and rotational speed difference.
Taking the axial thermal convection model of the solar polar region, it can
generate axial differential rotation, and the centrifugal force difference
generated by the axial differential rotation drives the meridional circulation,
transporting angular momentum away from the axis of rotation, forming
latitudinal differential rotation. The rotation of the fluid cell generates
additional pressure and change the convection criterion. The temperature
gradient in the solar troposphere is higher than in the non-rotating fluid
model, It's the energy source of the differential rotating.
