In the present study the mechanisms of evolution of propeller tip and hub vortices in the transitional region and the far field are investigated experimentally. The experiments involved detailed time-resolved visualizations and velocimetry measurements and were aimed at examining the effect of the spiral-to-spiral distance on the mechanisms of wake evolution and instability transition. In this regard, three propellers having the same blade geometry but different number of blades were considered. The study outlined dependence of the wake instability on the spiralto- spiral distance and, in particular, a streamwise displacement of the transition region at the increasing inter-spiral distance. Furthermore, a multi-step grouping mechanism among tip vortices was highlighted and discussed. It is shown that such a phenomenon is driven by the mutual inductance between adjacent spirals whose characteristics change by changing the number of blades.

Mario, F., Camussi, R., Fabio Di, F. (2011). Mechanisms of evolution of the propeller wake in the transition and far fields. JOURNAL OF FLUID MECHANICS, 682, 5–53 [10.1017/jfm.2011.150].

Mechanisms of evolution of the propeller wake in the transition and far fields

CAMUSSI, ROBERTO;
2011-01-01

Abstract

In the present study the mechanisms of evolution of propeller tip and hub vortices in the transitional region and the far field are investigated experimentally. The experiments involved detailed time-resolved visualizations and velocimetry measurements and were aimed at examining the effect of the spiral-to-spiral distance on the mechanisms of wake evolution and instability transition. In this regard, three propellers having the same blade geometry but different number of blades were considered. The study outlined dependence of the wake instability on the spiralto- spiral distance and, in particular, a streamwise displacement of the transition region at the increasing inter-spiral distance. Furthermore, a multi-step grouping mechanism among tip vortices was highlighted and discussed. It is shown that such a phenomenon is driven by the mutual inductance between adjacent spirals whose characteristics change by changing the number of blades.
2011
Mario, F., Camussi, R., Fabio Di, F. (2011). Mechanisms of evolution of the propeller wake in the transition and far fields. JOURNAL OF FLUID MECHANICS, 682, 5–53 [10.1017/jfm.2011.150].
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/118771
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 297
  • ???jsp.display-item.citation.isi??? 272
social impact