Model- and full-scale tip-raked marine propellers : analysis of the scale effects in open water conditions

This paper proposes the numerical investigation of the scale effects in open water for two tip-raked marine propellers. The turbulence model k − ω SST is applied for full-scale simulations, while the transition model γ − Reθ is used in model-scale. The hydrodynamic performance at different loading conditions is analyzed, and predictions indicate small Reynolds number effects for these two unconventional propellers. Whereas the predicted propeller efficiency is within a 2% relative deviation from measurements in model-scale, efficiency predictions in full-scale quantitatively deviate from the extrapolated-to-full-scale values, particularly at high advance ratios. Skin friction distributions and limiting streamlines at model-, with and without transition model, and full-scale are analyzed at the design conditions. It is concluded that the negligible predicted scale effects are related to the considerably dissimilar boundary layer flows at different Reynolds numbers and to the vortex shedding behind the blunt trailing edge for one of the two propellers. Finally, it is noted that k−ω SST predicts more significant scale effects than γ − Reθ when also used to compute model-scale results. This behavior emphasizes the importance of using a transition model for low-Reynolds number flows.

Subjects

Tip-Raked Marine Propellers

Scale Effects

Transition Models

DDC Class

620: Engineering

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publishedVersion

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http://rightsstatements.org/vocab/InC/1.0/

Name

Rubino-ModelAndFullscaleTiprakedMarinePropellersAnalysisOfTheScaleEffec-1145-1-final.pdf

Type

Main Article

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9.71 MB

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Adobe PDF

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Model- and full-scale tip-raked marine propellers : analysis of the scale effects in open water conditions