(142bs) Direct Numerical Simulation of Elastic Turbulence in Taylor-Couette Flow of Dilute Polymeric Solutions

Direct Numerical Simulation (DNS) of elastic turbulence has posed tremendous challenges to researchers engaged in developing first principles models and simulations that can accurately and robustly predict complex spatio-temporal behavior of viscoelastic flows.  To this end, we have focused our attention in performing DNS of elastic turbulence in a prototypical curvilinear flow, namely, the Taylor-Couette (TC) flow. Our computations with a prototypical constitutive equation for dilute polymeric solutions, namely, the FENE-P model are capable of reproducing the essential features of the experimentally observed elastic turbulence in TC flow of this class of fluids, i.e., randomly fluctuating fluid motion excited in a broad range of spatial and temporal scales. Moreover, the experimentally measured Power Spectral Density (PSD) of the radial velocity fluctuations with two continuous regions of power-law decay, namely, -1.1 and -2.2 at low and high frequencies is accurately captured. In addition, careful examination of the probability density functions (PDFs) of the velocity and polymer stress fluctuations show that highly localized “turbulent-like” flow structures in the wall region are mainly responsible for the stochastic characteristics of the flow.