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| Titel |
Dual plane PIV investigation of acoustically excited jets in a swirl nozzle |
| VerfasserIn |
G. S. Regunath, W. B. Zimmerman, J. M. Rees |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
2198-5634
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics Discussions ; 2, no. 5 ; Nr. 2, no. 5 (2015-09-04), S.1407-1424 |
| Datensatznummer |
250115195
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| Publikation (Nr.) |
 copernicus.org/npgd-2-1407-2015.pdf |
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| Zusammenfassung |
| A novel dual-plane dye laser PIV technique used to analyze helicity and
energy dissipation in an unexcited turbulent swirling jet of pressurized cold
air has established that regions within the flow field of the jet exhibiting
high helicity are correlated with regions of high turbulent kinetic energy
dissipation. This PIV configuration provides estimates of all components of
the velocity gradient tensor, facilitating calculation of the helicity from
the vorticity components. Application of this novel dual-plane PIV technique
is extended in this study to investigate helical structures in a turbulent
swirling jet where the underlying shear flow is subjected to external
acoustic sinusoidal forcing in a plane perpendicular to the central axis of
the jet. It was found that acoustic excitation had a significant effect on
the mean velocity profile parallel to the direction of the jet. The
horizontal forcing resulted in the generation of vorticity that was skewed
with a pitch that favored a distribution of angles around 90° with
respect to the velocity vector. The distribution of the time-averaged
helicity angle indicated organized helical activity, but such activity is not
dominated by large-scale coherent structures of maximal helicity. |
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