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Measurements of velocity-pressure correlation in various free shear flows

[ lundi 09-06-2008 18:00 | français ]Measurements of velocity-pressure correlation in various free shear flows Yoshitsugu NAKA School of science for open and environmental systems
Keio University

Résumé :
The pressure fluctuation and its correlation with velocity are one of fundamental characteristics of turbulent flows. We have been focusing on a technique for the experimental investigation of fluctuating pressure and its related statistics. We used two different types of miniature pressure probes: a small fluctuating static pressure probe (SP-probe) and a total pressure probe (TP-probe). These two different methods have pros and cons. Using SP-probe, static pressure fluctuation can directly be measured, but it is difficult to achieve the better spatial resolution in simultaneous measurement of velocity and pressure. The TP-probe has opposite characteristics against SP-probe. It has good spatial resolution but fluctuating static pressure are indirectly calculated. We have investigated the basic performance of our measurement systems such as the frequency response and the effect of angle of attack of the probe. The technique has been applied for various free shear flows (e.g. mixing layer, jet, wake and wingtip vortex). In the presentation, a part of our results will be introduced. For example, in the case of the mixing layer, our results are compared with the DNS result and simple turbulence model by Lumley (1978).
The research activities in our laboratory (Prof. S. Obi and Prof. K. Fukagata) will also be introduced. The research topics cover wide area of fluid mechanics especially focused on turbulent flows. The approach is both from numerical simulation as well as experimental techniques. The facilities, techniques and some results will be presented on their research activities.