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DY: Fachverband Dynamik und Statistische Physik
DY 42: Turbulence
DY 42.9: Vortrag
Mittwoch, 14. März 2018, 12:15–12:30, BH-N 128
The Statistical Properties of Ultra-Strong Turbulence — •Christian Küchler1, Gregory P. Bewley2, and Eberhard Bodenschatz1 — 1Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany — 2Cornell University, Ithaca, USA
How do the two-point statistical quantities of the velocity field depend on the turbulence level? Is turbulence universal? Answering these questions requires access to a sufficiently wide inertial range over which the turbulence can be considered universal. The Variable Density Turbulence Tunnel at the Max Planck Turbulence Facility can reach extremely high turbulence levels under experimentally resolvable conditions. The VDTT is a closed- loop wind tunnel of 80 m3 volume filled with pressurized sulfur-hexaflouride at 0.5 bar to 15 bar. This allows to change the turbulence levels over two orders of magnitude, while keeping the geometry of the flow the same. The turbulence is generated by an unique active grid consisting of 111 individually controllable flaps. By using nanoscale thermal anemometry probes developed at Princeton University we record ultra long time series of the turbulent velocity field at a single point 9 m downstream of the active grid. Using these techniques we compiled datasets at turbulence levels that hereto-forth could not experimentally resolved. In the talk we report the evolution of two-point statistics as a function of turbulence level and present insights on the inertial range scaling and intermittency effects of turbulent flows.