  We demonstrate that the orbital angular momentum flux density of a paraxial
light beam can change on propagation in free space. These changes are entirely
due to the spatial coherence state of the source, and the effect is analogous
to correlation-induced changes in the intensity, spectrum and polarization of a
beam. The use of the source coherence state to control the width, shape, and
transverse shifts of the OAM flux density is demonstrated with numerical
examples.
