(296b) Curvature Dependence of Viscoelastic Turbulent Taylor-Couette Flows

We report direct numerical simulation results that clearly elucidate the mechanism that leads to curvature dependence of drag increase (DI) in viscoelastic turbulent Taylor-Couette flow. Specifically, changes in the angular momentum transport and their inherent link to transitions in vortical flow structures have been explored to depict the influence of the curvature of the flow geometry on DI. To this end, for small radius ratio (η), Newtonian large-scale Taylor vortices become unstable by polymer additives and give way to small-scale Görtler vortices that enhance the incoherent transport leading to homogenization of the polymer stress, τ^p_rθ and larger DI. At large η this flow transition does not occur, hence, elastically modified Taylor vortices remain intact and enhance transverse transport resulting in much higher coherent angular momentum flux and smaller DI. The present finding paves the way for capturing highly localized elastic turbulence structures in direct numerical simulation by increasing geometry curvature in traditional turbulent curvilinear flows.