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

By Mario Felli, R. Camussi, Fabio Di Felice. Journal of Fluid Mechanics, 2011

399 citations recorded by the source corpus.

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 spiral-to-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.

Subfields: Aerospace Engineering, Mechanics of Materials, Ocean Engineering

View Paper: https://www.semanticscholar.org/paper/864e8408a349c8e947c322405a994f9cd0f93b03

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Citations in the corpus

Tip-vortex instability and turbulent mixing in wind-turbine wakes (2015, background): “The expected changes will be a more unstable wake, with earlier leapfrogging, as shown experimentally by Felli et al. (2011); also, the unstable tip vortices will not form pairs, but groups of three, as shown in the visualisation of Bolnot et al. (2014).”
Experimental analysis of the wake of a horizontal-axis wind-turbine model (2014, background): “[8,11,21] showed the influence of different parameters (such”
Large eddy simulation of propeller wake instabilities (2017, methodology): “…of blade trailing edge wake generates concentrated vortices which subsequently interact with the tip vortices causing wake instability, is different from that observed in experiments (Di Felice et al. 2004; Felli et al. 2011) and is not reported in the literature to the best of our knowledge.”
Wind-Turbine and Wind-Farm Flows: A Review (2019, background): “Several wind-tunnel and numerical studies (e.g., Felli et al. 2011; Iungo et al. 2013a; Viola et al. 2014; Ashton et al. 2016) have shown that the hub vortex is characterized by a singlehelix counter-winding instability, which interacts with the tip-vortex layer (e.g., Okulov and Sørensen 2007;…”
On the interaction between a turbulent open channel flow and an axial-flow turbine (2013, background): “As mentioned, hub-vortex instability (Felli et al. 2011), wake expansion and vortex diffusion may be involved in this process.”
On the wake dynamics of a propeller operating in drift (2014, methodology): “This behaviour is in excellent agreement with experiments (Felli et al. 2011), where it is shown that, for this condition, the instability starts around sW = 10.”