In spanwise rotating channel flows, the turbulent kinetic energy near the high pressure and the low pressure walls is primarily associated with longitudinal velocity fluctuations. Consequently, the primary normal Reynolds momentum flux difference is positive and the secondary normal Reynolds flux difference is negative. In the outer region on the high pressure side of the symmetry plane, the energy is redistributed with the result that the signs of both the primary and of secondary normal differences flip. This redistribution of energy by Coriolis forces occurs in a region of zero intrinsic vorticity. In this paper, the dispersion of a passive additive within the zero intrinsic vorticity region is examined by using a recently developed universal, realizable, anisotropic prestress closure for the normalized Reynolds stress. For low rotation numbers (i.e., |Ω_x|《 ε / k ), the theory shows that the transversecomponent of the passive additive flux is mitigated by a coupling between the shear component of the Reynolds stress and the longitudinal gradient of the mean passive additive field. At high rotation numbers (i.e., |Ω_x|》ε/k), the dispersioncoefficient in the transverse (cross flow) direction is four times larger than the dispersion coefficient in the spanwise direction. Surprisingly, the dispersion coefficient in the longitudinal direction is relatively small. The geophysical and the engineering significance of these theoretical conclusions will be highlighted in the presentation.
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