Dresden 2006 – wissenschaftliches Programm
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DY: Dynamik und Statistische Physik
DY 38: Fluid Dynamics
DY 38.5: Vortrag
Mittwoch, 29. März 2006, 17:45–18:00, SCH 251
Statistics of temperature fluctuations measured by a new microscopic temperature sensor — •Florian Heidemann, Marco Munzel, and Achim Kittel — University of Oldenburg, D-26111 Oldenburg
The basic principals of turbulence are still not well understood. On the basis of the measurements in a homogeneous isotropic free jet it is possible to characterize its invariant parameters and investigate the nature of turbulence. We have analyzed a heated free jet of water in a water tank with a new developed fast thermosensor with a high spatial and temperature resolution at different positions and for different flow velocities. The used nozzle has a diameter of 2mm, which provides a laminar flow with a rectangular velocity profile at the outlet. The sensor is based on a miniaturized thermocouple and has an active area of approx. 0.05µ m2 and a response time of approx.10 µ s in water with a temperature resolution of 50mK (measured with a bandwidth of 100kHz). Our aim is to characterize the temperature fluctuations perpendicular and parallel to the symmetry axis of the free jet with power spectra and increment distributions depending on the position with respect to the nozzle. Furthermore the measured fluctuations are analyzed with the markov analysis.