We study the velocity shear which has been reported to exist between plumes and the interplume flow in coronal holes. The shear between two uniformly, magnetized regions can be unstable and evolve into a new less sheared pattern. We model fine scale velocity structures associated with the Kelvin-Helmholtz instability. We believe these fine structures could be part of the process of mixing of plume with interplume flow. When carried further downstream, the resultant momentum exchange may eliminate the shear and lead to the observed smooth high speed wind.