%0 Journal Article
%A Mahfouz, F. M.
%D 2009
%I Begell House
%N 5
%P 424-446
%R 10.1615/InterJFluidMechRes.v36.i5.30
%T Impulsively Started Flow of a Micropolar Fluid Past a Circular Cylinder
%U http://dl.begellhouse.com/journals/71cb29ca5b40f8f8,020d75970b05b2e4,02b2107d7457c2f7.html
%V 36
%X The characteristics of the unsteady laminar impulsive flow of micropolar fluid over a horizontal circular cylinder is investigated. The conservation equations for mass, linear momentum and angular momentum are solved in order to determine the flow structure and associated hydrodynamic forces and couple. The main controlling parameters are Reynolds number and material parameters of micropolar fluid. The dimensionless material parameters are the vortex viscosity, the spin gradient viscosity and the micro-inertia density. These parameters are selected in the range from 0 to 10 while the Reynolds number is considered up to 180. The results have shown that the micro-inertia density has no effect on micropolar fluid flow characteristics while the effect of both vortex viscosity and spin gradient viscosity is noticeable. The study has shown that both the Strouhal number and the amplitude of oscillating lift force decrease with the increase of vortex viscosity and with the increase, but with a little degree, of spin gradient viscosity. The results have revealed that the drag coefficient does not exhibit a clear general trend as the material parameters vary. The damping effect of micropolar fluid on vortex shedding process should draw the attention to artificially made micropolar fluids as a possible control method for flow separation.
%8 2009-09-07