Berlin 2012 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 37: Poster: Rheology (joint focus with DRG)
CPP 37.6: Poster
Donnerstag, 29. März 2012, 18:45–19:45, Poster A
Decay of elastic turbulence in a von Karman swirling flow — •Christof Schäfer1, Teodor Burghelea2, and Christian Wagner1 — 1Experimental Physics, Saarland University, 66123 Saarbrücken, Germany — 2Laboratoire de Thermocinétique, University of Nantes, Nantes 44306, France
We present results of the experimental study of the decay of elastic turbulence in a von Karman swirling flow. We characterize various decay regimes by combined measurements of the integral power injected into the system and local measurements of the velocity gradients as a function of the initial Weissenberg number. Following relevant literature [1] a detailed description of the time evolution of the decaying flow structures is given. The characteristic decay time scales of the locally measured velocity gradients in both the bulk and in the elastic boundary layer of the flow is compared to the characteristic decay times of the integral power, the Eulerian correlation time of velocity fields and the largest relaxation time of the polymer solution. Based on these results, the possibility of exciting nonlinearly unstable states from an initially linearly stable base state is discussed.
[1] T. Burghelea, E. Segre, and V. Steinberg, "Elastic turbulence in a von Karman swirling flow between disks", Phys. Fluids 19, 053104 (2007)