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Titel:

Correlations between Turbulent Wall Pressure and Velocity Field Fluctuations in Backward-Facing Step Flows

Autor(en): I. Bolgar, S. Scharnowski, C.J. Kähler
Zusammenfassung: The combination of high-resolution planar PIV with high frequency dynamic pressure transducers allows for the correlation of velocity field fluctuations with wall pressure fluctuations. This technique was successfully applied at the TWM facility in order to resolve the driving flow mechanisms that create the dynamic pressure loads aft of a BFS. Experiments at Ma[infinity] = 0.8 were conducted, while PIV and pressure data were recorded simultaneously over 33s at 15 Hz and 25 kHz, respectively. By offsetting the pressure data, which is correlated with the PIV images by a few samples, it is possible to statistically track the dominant flow phenomenon in space and time, thus artificially increasing the temporal resolution of PIV. This allows for the determination of important fluid mechanic properties such as the convection velocity of the dominant fluid motion, as well as the vortex shedding frequency. The results show that the most dominant phenomenon exciting the dynamic loads aft of a BFS are the Kelvin-Helmholtz vortices in the reattaching shear layer, occuring at a Strouhal number normalized to the step height of Srh = 0.13.
Veranstaltung: Deutscher Luft- und Raumfahrtkongress 2017, München
Verlag, Ort: Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn, 2017
Medientyp: Conference Paper
Sprache: englisch
Format: 21,0 x 29,7 cm, 10 Seiten
URN: urn:nbn:de:101:1-2017092216889
Stichworte zum Inhalt: Heckströmung von Trägerraketen, TR40
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Veröffentlicht am: 22.09.2017