The Possibility of the Kelvin-Helmholtz Instability during Sedimentation of Dust Grains in the Protoplanetary Disk

We reexamine the possibility of shear-driven turbulence during the sedimentation of dust grains in the protoplanetary disk. Shear-driven turbulence is expected to occur before the onset of a gravitational instability for the MMSN model. However, according to previous studies that did not account of the growth of dust grains, with a larger abundance of dust grains, the gravitational instability is indicated to occur before shear-driven turbulence. In this paper, the case including dust growth is considered, and it is found that a Kelvin-Helmholtz instability tends to occur before the gravitational instability, even in the case with a large abundance of dust grains. This is different from previous results without the dust growth.