Flow of micropolar fluid between two orthogonally moving porous disks

The unsteady, laminar, incompressible, and two-dimensional flow of a micropolar fluid between two orthogonally moving porous coaxial disks is considered. The extension of von Karman's similarity transformations is used to reduce the governing partial differential equations (PDEs) to a set of non-linear coupled ordinary differential equations (ODEs) in the dimensionless form. The analytical solutions are obtained by employing the homotopy analysis method (HAM). The effects of various physical parameters such as the expansion ratio and the permeability Reynolds number on the velocity fields are discussed in detail.