CHARACTERiZATION OF FLOW REGIMES FOR SHEAR THINNING FLUID FLOW ACROSS A CHANNEL CONFINED CIRCULAR CYLINDER

Abstract

The limiting conditions for the flow separation and steady symmetric flow regimes for the - poiseuille flow of incompressible shear-thinning and Newtonian fluids across a channel confined circular cylinder has been investigated numerically by solving the above equations with physically realistic boundary conditions using OpenFOAM (Version 2.3). Extensive results showing the effect of power law index (n) and blockage ratio ( ) on the formation of wake and onset of wake asymmetry have been presented for wide range of power law index (0.2 < n < 1) and blockage ratio (1.1 < 0 < 4). The critical values of Reynolds number have been presented showing the transition between the flow regimes. The corresponding values of drag and lift coefficients along with the critical Strouhal number (S1) have also been presented for the critical values of Reynolds number. In contrast with unconfined flow the critical Reynolds number for the wake formation decreases as the power law index (n) decreases. Whereas the complex dependence of critical Reynolds number for the onset of wake instability on power law index (n) shows the same trend as that for unconfined flow. A - series of streamline patterns have also been presented to get the detailed insight of the flow kinematics.