Karman Vortex Shedding in Non-Newtonian Blood-Mimicking Fluids

Bluff body wakes and vortex shedding have been extensively studied for Newtonian fluids, but they remain relatively unexplored for non-Newtonian fluids. The nonlinear behavior of such fluids widens the parameter-space of the problem, making its characterization difficult. Shear-dependent viscosity is perhaps the most widely modeled constitutive nonlinearity with several inelastic, rheological models proposed in literature. The Carreau-Yasuda model has been used increasingly to model the shear-thinning behavior of blood, however, computational work with this model has been largely restricted to creeping and steady flows. To the best of our knowledge, no data exists in literature for transient Carreau-Yasuda flow over cylinders. To bridge this gap, we present simulation results for unsteady, two-dimensional, shear-thinning Carreau flow over a circular cylinder. We fix the characteristic Reynolds number at 100 and quantify the effect of varying rheological model parameters on the time-varying and mean forces on the cylinder and the vortex-shedding frequency. These results also provide benchmarking data for computational models of non-Newtonian flows, especially those relevant to hemodynamics.