Steady and unsteady non-Newtonian inelastic flows in a planar T-junction

Abstract

Steady and unsteady laminar flows in a planar 2D T-junction, having a dividing or bifurcating flow arrangement (one main channel with a side branch at 90°), are studied numerically for non-Newtonian inelastic fluids whose rheological characteristics are similar to those of blood. These computational fluid dynamics simulations explore a wide range of variation of inertia (through the Reynolds number, Re), flow rate ratio (proportion of extracted to inlet flow rates, β) and shear thinning (the power-law index of the model, n), and investigate their influence on the sizes and intensities of the recirculating eddies formed near the bifurcation, and on the resulting distribution of the shear stress fields. Such flow characteristics are relevant to hemodynamics, being related to the genesis and development of vascular diseases, like the formation of atherosclerotic plaques and thrombi near arterial bifurcations.To represent the decay of viscosity with shear rate we apply the Carreau-Yasuda equation, one of the most utilized Generalized Newtonian Fluid model in blood simulations. In many comparisons of the present parametric study it was require that the level of inertia was kept approximately the same when n was varied. This implied a consistent definition of Re with the viscosity calculated at a representative shear rate.