From the summary: We consider the unsteady three-dimensional Kármán flow induced by impulsive rotation of an infinite rotating plane immersed in an incompressible viscous fluid with a dilute suspension of small solid monodisperse spherical particles. The flow is described in terms of a dusty gas model, which treats the discrete phase (particles) and the continuous phase (fluid) as two continua occupying the same space and interacting through Stokes drag mechanism. The model is extended to allow for a local gravitational acceleration in a direction parallel to the axis of rotation, and is valid for cases in which gravity acts either in the same direction as or in the opposite direction to Ekman axial flow induced by the rotation of the plane.