Analytical studies on MHD oscillatory flow of a micropolar fluid over a vertical porous plate

In recent years, the dynamics of micropolar fluids, originated from the theory of Eringen (J. Math. Mech., 16 (1964) 1), has been a popular area of research. As the fluids consist of randomly oriented molecules, and as each volume element of the fluid has translation as well as rotation, the analysis of physical problems in these fluids has revealed several interesting phenomena, which are not found in Newtonian fluid. In this study, we investigate the problem of the oscillatory two-dimensional laminar flow of a viscous incompressible electrically conducting micropolar fluid over a semi-infinite vertical moving porous plate in the presence of a transverse magnetic field. Here, it is assumed that the size of holes in the porous plate is much larger than a characteristic microscopic length scale of the micropolar fluid to simplify formulation of the boundary conditions. The effects of various flow parameters and thermophysical properties on the flow and temperature fields across the boundary layer are investigated. Especially, the effects of non-zero values of micro-gyration vector on the velocity and temperature fields across the boundary layer are studied, using the method of small perturbation approximation. Numerical results of velocity profiles of micropolar fluids are compared with the corresponding flow problems for a Newtonian fluid. The results also show that there exists completely oscillating behavior in the velocity distribution.