Separated flows behind afterbodies in the high subsonic regime are investigated experimentally. Measurements or mean and unsteady wall pressure have been performed in a transonic wind tunnel on axisymmetric configurations with a propulsive jet. It is found that the distance between the base plane and the nozzle exit section, namely, the rear-body extension, is a determining parameter. For a long enough rear-body extension, the separated flow reattaches at the end of the external nozzle wall. The spectra in the reattachment region exhibit a weakly defined maximum, which is associated with the shear layer vortices impinging the downstream surface. For a short rearbody extension, the reattachment on the downstream nozzle wall is not possible. The spectra in the whole region exhibit a well-defined periodicity that corresponds to the formation of large-scale structures in the wake, as observed for bluff bodies. This is confirmed by a two-point correlation analysis of the turbulent signals, which shows that the flow is dominated by a highly coherent antisymmetric mode at the vortex shedding frequency.
Analysis of unsteadiness in afterbody transonic flows
Analyse Druckschwankungen im Heckbereich transsonisch umströmter Rotationskörper
AIAA Journal ; 42 , 12 ; 2541-2550
2004
10 Seiten, 19 Bilder, 1 Tabelle, 21 Quellen
Aufsatz (Zeitschrift)
Englisch
Abreißen der Strömung , Druckmessung , Druckschwankung , Druckverteilung , Düsenabstand , Freistrahl , Frequenzgang , instationäre Strömung , Nachlaufströmung , räumliche Kohärenz , Scherströmung , Strahlantrieb , Strömung an Rotationskörpern , Totzone , Transschallwindkanal , transsonische Strömung , Turbulenzgrad , Überschallströmung , Windkanalprüfung , Wirbelablösung , Axialsymmetrie , Korrelationsanalyse
Analysis of Unsteadiness in Afterbody Transonic Flows
AIAA | 2004
|FLUID DYNAMICS - Analysis of Unsteadiness in Afterbody Transonic Flows
Online Contents | 2004
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