Study of Chaotic Flows in Non-Newtonian Fluids at Low Reynolds Numbers

With the advent of technologies related to the miniaturization of devices, the ability to predict the fluid motion in and around these devices assumes importance for their design and optimization. Because of the small dimensions and very low speeds that are involved, the flows within these components are generally laminar. Such laminar flows are a consequence of the limitations imposed by viscous stresses and the devices associated with them are important for a range of applications in areas such as pharmaceutics, medicine, heat transfer, biomedical engineering, and electronics cooling. In every case, the devices associated with these application areas would generally benefit by augmented transport of a scalar and/or heat to facilitate the processes which are underway. Polymer additives, such as polyacrylamide, have unique characteristics in liquids, including highly non-linear, viscoelastic behavior. The extensibility of the polymer and the resulting polymer deformation leads to a sharp growth in the local elastic stress. This gives rise to an instability that develops into turbulence in a sequence of events referred to as the elastic turbulence. Such changes also increase the mixing of scalars and enhance heat transfer in the fluid flow. The afore-mentioned chaotic flow at vanishingly low Reynolds number called elastic turbulence is a strongly fluctuating regime of fluid flow. This phenomenon, observed in viscoelastic polymer solutions is driven by the strong coupling between the fluid velocity and its elasticity. Current research is an attempt to numerically capture the phenomenon by developing a generalized 3D module to solve hyperbolic viscoelastic partial differential equations in ANSYS-FLUENT and thereby provide some insight into the phenomenon