Berlin 2005 – wissenschaftliches Programm
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DY: Dynamik und Statistische Physik
DY 14: Complex Fluids
DY 14.3: Vortrag
Freitag, 4. März 2005, 16:00–16:15, TU H3010
Shear thickening, stick-slip like flow behavior and rheo-chaos in non-linear Maxwell model fluids — •Siegfried Hess1 and Ortwin Hess2 — 1Inst.f.Theoret.Physik, TU Berlin — 2Advanced Technology Institute, School of Electronics and Physical Sciences, University of Surrey, Guildford, GU2 7XH, UK
The nonlinear Maxwell model equation for the stress tensor as introduced previously in O. Hess and S. Hess, Physica A 207 (1994) 517 to treat the shear thickenening and shear thinning behavior of fluids can also be applied for temperatures and densities where a substance shows a yield stress. The basic equations are discussed. Analytic and mainly numerical results are presented for the plane Couette flow geometyry. Depending on the model parameters and on the imposed sheat rate, a stationary state can be reached or not. In the second case periodic solutions of stick-slip like motions or irregular chaotic behavior is found. For some typical cases the shear stress, the first and second normal stress differences as well as the stress components which break the Couette symmetry are displayed as functions of the time. Different types of time dependent solutions can be distinguished by the rheological phase portraits. Some remarks are made on the entropy production associated with the viscous flow and the stress relaxation.