Modeling of the turbulent transport coefficients in a gas- dust accretion disk

An heuristic way of modeling the turbulent exchange coefficients for Kepler ian accretion disks surrounding solar-type stars is considered. The formula s for these coefficients, taking into account the inverse effects of dust t ransfer and potential temperature on the maintenance of shear turbulence, g eneralize to protoplanetary gas-dust clouds the expression for the turbulen t viscosity coefficient in so-called alpha -disks which was obtained in a c lassic work by Shakura and Syunyaev (1973). The defining relationships are derived for turbulent diffusion and heat flows, which describe, for the two -phase mixture rotating differentially at an angular velocity Omega (r, z), the dust and heat transfer in the direction perpendicular to the central p lane of the disk. The regime of limiting saturation by small dust particles of the layer of "cosmic fluid" located slightly above (or below) the dust subdisk is analyzed.