  We discuss a mean-field theory of generation of large-scale vorticity in a
rotating density stratified developed turbulence with inhomogeneous kinetic
helicity. We show that the large-scale nonuniform flow is produced due to ether
a combined action of a density stratified rotating turbulence and uniform
kinetic helicity or a combined effect of a rotating incompressible turbulence
and inhomogeneous kinetic helicity. These effects result in the formation of a
large-scale shear, and in turn its interaction with the small-scale turbulence
causes an excitation of the large-scale instability (known as a vorticity
dynamo) due to a combined effect of the large-scale shear and Reynolds
stress-induced generation of the mean vorticity. The latter is due to the
effect of large-scale shear on the Reynolds stress. A fast rotation suppresses
this large-scale instability.
