Analysis of the Unsteady Flow Around a Hydrofoil at Various Incidences
Chapitre d'ouvrage scientifique
Abstract
The oscillating hydrofoils used in underwater propulsion devices often experience large variations of the flow incidence, which favors cavitation at large angle of attack, and therefore a severe degradation of the performance, additional flow instability, and even cavitation erosion. These various phenomena make numerical simulations of the flow around oscillating hydrofoils quite challenging, especially in cases where the laminar-turbulent transition usually occurs when the blade has a high angle of attack. In the present study, the unsteady flow around a stationary Clark-Y hydrofoil is simulated at five fix incidence angles using the Star CCM+ software. The results show that the lift coefficient increases continuously with the incidence angle up to 15°, even after a separation vortex is generated near the trailing edge. Then, as a slight stall occurs at 20°, the lift coefficients obtained with the k-ω SST and SST Re teta transition models become significantly different, mostly because of the different prediction of laminar to turbulence transition at the hydrofoil leading edge. Under deep stall condition at 25°, the flow is much more complex and the hydrofoil performance decreases dramatically. The lift force predicted by the SST transition model is more periodic than with the SST k-ω model. Although the general vortex evolution predicted by the two turbulence models is similar, the local pressure experiences larger amplitude variations with the k-ω SST model, as can be also observed from the evolution of the lift coefficient.
Files in this item
Related items
Showing items related by title, author, creator and subject.
-
Article dans une revue avec comité de lectureThe goal of the present work deals with the influence of the oscillating freestream on the global performance, transition and vortex dynamics of forward and reversed airfoils. Three important parameters, involving the ...
-
Article dans une revue avec comité de lectureThe laminar-turbulence transition phenomenon widely exists on the surface of many energy equipment, which is deserved to be studied because of the complex mechanics and some induced undesirable consequences. The goal of ...
-
Article dans une revue avec comité de lectureWANG, Yefang; SHI, Lei; BAYEUL-LAINÉ, Annie-Claude; COUTIER-DELGOSHA, Olivier (SAGE Publications, 2022-11)Recently, lots of oscillating targets inspired from motions of some insects and birds have been applied extensively to many engineering applications. The aim of this work is to reveal the performance and detailed flow ...
-
Article dans une revue avec comité de lectureAs a new type of the propulsive devices, cycloidal rotor has been attracting more attention recently. The present work concentrates on the analysis of the performance and internal flow field of a two-bladed cycloidal ...
-
Article dans une revue avec comité de lectureThe unsteady vortical flows and laminar-turbulence transition over a 2-bladed cycloidal rotor are investigated numerically at two advance coefficients, with special emphasis on the influence of two turbulence models, ...