Regensburg 2007 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 5: Fluid dynamics I

DY 5.3: Talk

Monday, March 26, 2007, 14:45–15:00, H2

Correlation measurements of temperature and velocity in turbulent flows — •Marino Beenhakker, Michael Hölling, Stephan Barth, Marco Munzel, Joachim Peinke, and Achim Kittel — Institut für Physik, Universität Oldenburg

The knowledge of the statistics of velocity and temperature fluctuations at a certain position in turbulent flow is important for the development of theory on turbulence. Two different sensors are presented to measure flow velocity and temperature of fluids.

A Laser-Cantilever-Anemometer (LCA) detects the flow velocity by means of the deflection of a microscopic cantilever. The measurement principle is predestined to be combined with a temperature measurement because in contrast to a hot wire anemometer the fluid is not heated. The high-speed thermometer used is based on submicrometer-size thermocouples. The thermocouple is formed at the tip of a glass-micropipette with a platinum core and a coating of gold. Both sensors are embedded in waterproof shielded enclosures which both include a preamplification circuit. These type of sensors are able to measure with high spatial and temporal resolution and small crosstalk which is necessary for correlation measurements.

The characterization features of both sensors are discussed and compared with other methods.