Reynolds stresses and differential rotation. I. On recent calculations of zonal fluxes in slowly rotating stars

Abstract

In order to derive general zonal flux expressions this paper deals with the influence of slow (Ωτ<1) rotation on highly anisotropic stochastic motions. The radial and latitudinal fluxes of angular momentum are derived and depend on two spectral functions. The results are applied to the often used example of spatially periodic correlations, i.e., to one-mode spectra. The zonal fluxes in this case can be expressed as combinations of the intensities of the three velocity components and the wave number vector. Specializing these quantities to the cases discussed in the literature. we are able to reproduce previously published results. Moreover, after a replacement of the ensemble averages by those over the longitudinal coordinate, fluxes result which hare been derived for non-axisymmetric modes with l=m. Thus, a fairly complete account is given of results published in this field up to the present.