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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 40: Polymer and Molecular Dynamics, Friction and Rheology
CPP 40.5: Vortrag
Dienstag, 17. März 2020, 12:00–12:15, ZEU 255
The instability onset behavior of viscoelastic Taylor-Couette flow as a combined function of flow geometry and rheological parameters: purely elastic versus thermo-elastic instabilities — •Reza Ghanbari1,3 and Bamin Khomami1,2 — 1MRAIL (Material Research and Innovation Lab), Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, USA — 2Sustainable Energy and Education Research Center (SEERC), University of Tennessee, Knoxville, USA — 3Present: Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700 Fribourg, Switzerland
Linear stability analysis of Taylor-Couette flow (TCF) of dilute polymer solutions has been performed by using prototypical constitutive equations for polymeric solutions, namely, the Oldroyd-B & the FENE-P models. The hydrodynamic stability characteristics of the flow in the presence & absence of thermal effects & in the limit of vanishing fluid inertia have been determined using an eigenvalue analysis. Particular attention has been paid to determine the instability onset conditions as a function of fluid thermal sensitivity & gap ratio. We observed a reduction in the critical Weissenberg (Wic) for the instability onset as the gap ratio & fluid thermal sensitivity are enhanced. In particular, under non-isothermal conditions, Wic was reduced by almost an order of magnitude for all gap ratios. Our results suggest that recent experimental observations of purely elastic turbulence in the TCF at order (1) Wi were not performed under isothermal conditions. Hence, this new flow state should be labeled as thermo-elastic turbulence.